If your lawn is more mountain than meadow, you know the struggle of pushing a mower up a steep incline. Hilly yards demand a robot that won’t slip, stall, or lose its way. That’s where Mammotion’s lineup shines. In this guide, we evaluate the best Mammotion robot lawn mower for hilly lawns, focusing on models that handle slopes up to 80% with precision and reliability. Whether you have a gentle roll or a serious grade, we have a pick for you. For more on app-based control, check out our guide to Mammotion mowers with app control.
Pros
- No perimeter wire installation saves time and labor
- Handles steep slopes up to 40 degrees with ease
- Precise RTK cloud navigation maintains straight mowing patterns
- AI obstacle avoidance works reliably with various objects
- Automatic mapping and zone management via app
Cons
- High upfront cost compared to wire-based robotic mowers
- Requires cellular connectivity for GPS tracking and cloud features
- Setup may be complex for users unfamiliar with smart lawn equipment
The WORX WR342 Vision Cloud robotic lawn mower redefines wire-free mowing for homeowners with challenging terrain. Designed for up to half an acre, it combines commercial-grade RTK cloud positioning with Vision AI to deliver precise, autonomous cutting without the hassle of installing perimeter wires. This mower is ideal for those who want a premium, hands-off experience on slopes and uneven ground.
Standout features include true 4WD traction that handles slopes up to 84% (40 degrees) and a terrain-adaptive chassis that keeps all four wheels planted over bumps and transitions. The RTK cloud provides centimeter-level accuracy, while V-SLAM sensor fusion ensures reliable navigation under trees or shaded areas. AI obstacle avoidance, powered by a neural network, intelligently recognizes and avoids objects like toys, pets, and garden furniture, keeping mowing smooth and safe.
Build quality is robust, with a durable chassis and a cut-to-zero offset blade that trims closer to edges than most competitors. The app allows unlimited zone management, custom pathways, and remote control, plus GPS tracking with Find My Landroid for security. The mower can create straight, even stripes in patterns like parallel, checkerboard, or diamond, all selectable via the app.
Potential drawbacks include a high price point and the need for cellular connectivity for cloud features and GPS tracking. Setup may be more involved than simpler wire-based models, especially for users unfamiliar with smart lawn equipment. However, once configured, the WR342 offers a truly wire-free, low-maintenance mowing experience.
Overall, the WORX WR342 Vision Cloud is a top-tier choice for homeowners with sloped, irregular lawns who want the convenience of a robotic mower without perimeter wires. Its combination of 4WD, RTK precision, and AI intelligence makes it one of the most capable and user-friendly options on the market. If your budget allows and you value a clean, wire-free lawn, this mower is well worth the investment.
Pros
- Simple drop-and-mow operation, no smartphone required
- Parallel cutting for a clean, professional look
- Effective obstacle avoidance with ultrasonic sensors
- Long 6-hour runtime covers sizable lawns
- Affordable price point for a feature-rich robot mower
Cons
- Requires a well-defined lawn edge and occasional trimming for optimal performance
- Boundary setup uses physical magnetic strips, which may be less convenient than app-based virtual fences
- No user reviews yet, so long-term reliability is unproven
The LawnMaster OcuMow VBRM601YCM AD Robot Mower is designed for homeowners with small to medium lawns up to 2,600 square feet. It targets those who want a straightforward, app-free mowing solution that doesn't require complex setup or Wi-Fi connectivity.
Its key innovation is parallel cutting combined with optical navigation, which allows the mower to first trim the border and then cut the interior in neat, parallel lines. This results in a consistently manicured look. The ultrasonic obstacle avoidance keeps it away from garden furniture and kids' toys, and the 35% slope climbing capability handles gentle hills with ease.
The mower is built with deep tread wheels and a robust drive system, finished in a bright orange color for visibility. The included 24V 8.0Ah battery provides up to six hours of run time, and the magnetic strip boundary system is simple to lay out without any digging or power tools. The overall build feels durable for its price point.
One limitation is that the mower works best when your lawn has a clearly defined edge around the full perimeter. You may need to adjust edges and keep a grass trimmer handy for touch-ups. Also, the magnetic strip boundary system, while easy to set up, is less flexible than app-based virtual fences found on pricier models. Since this is a new product with no user reviews, long-term reliability remains to be seen.
For its price, the LawnMaster OcuMow offers a compelling blend of simplicity and performance. It's an excellent choice for anyone who prefers a no-fuss robotic mower that delivers a professional-looking cut without the need for smartphone apps. If you have a well-defined lawn and value ease of use over high-tech features, this mower is worth considering.
Color: Orange
Dimensions: 17.24 x 13.7 x 8.66 inches
Coverage: Up to 2,600 sq. ft.
Run Time: Up to 6 hours
Battery: 24V 8.0Ah (included)
Slope Climbing: Up to 35%
Boundary: Magnetic strip (49 ft included)
Includes: Robot mower, battery, charger, magnetic strip, pegs, extra blades
Pros
- Wire-free installation saves hours of burying perimeter wires.
- Dual navigation system maintains signal in challenging yard environments.
- AI vision obstacle avoidance reduces the risk of collisions with pets and objects.
- Handles steep slopes and uneven terrain with ease.
- App control offers flexible scheduling and real-time monitoring.
Cons
- Optional edge-cutting module and 4G anti-theft module are sold separately, adding to the total cost.
- No built-in rain sensor; may require manual intervention in wet conditions.
- Limited to 1/4 acre coverage, not suitable for larger lawns without additional units.
The Roborock RockNeo Q110H is a wire-free robotic lawn mower designed for homeowners with medium-sized yards up to 1/4 acre. It eliminates the hassle of installing perimeter wires, using advanced dual-mapping modes to chart your lawn quickly. This mower is perfect for those who want a set-and-forget solution for complex landscapes with trees, slopes, and garden features.
Its standout feature is the Full-Band RTK and VSLAM dual-navigation system, which maintains pinpoint accuracy even under dense tree canopies or near high fences. The AI vision obstacle avoidance uses dual cameras to understand and avoid static objects, pets, and people, ensuring a safe and continuous mowing session. The floating cutting deck adapts to ground contours, handling slopes up to 45% and obstacles up to 1.57 inches, making it versatile for uneven terrain.
Build quality is solid, with large-diameter wheels and a robust chassis that feels durable. The Roborock App provides comprehensive control, including multi-zone scheduling and real-time progress tracking. An optional edge-cutting module (sold separately) can achieve a 1.2-inch edge precision for a manicured look. Anti-theft features include a PIN code lockout and alarm, with an optional 4G tracking module for extra security.
Potential drawbacks include the lack of a built-in rain sensor, which means you may need to manually pause mowing in wet conditions. The optional modules, while useful, add to the overall investment. Additionally, the 1/4 acre coverage limit means larger properties may require multiple units or a different model.
Overall, the Roborock RockNeo Q110H is a top-tier choice for hassle-free lawn maintenance on medium-sized, complex yards. Its wire-free setup, reliable navigation, and intelligent obstacle avoidance make it a strong contender in the robotic mower market. If you value precision, safety, and app control, this mower delivers excellent performance.
Brand: Roborock
Model: RockNeo Q110H
Color: Black
Dimensions: 24.6 x 16.5 x 10.6 inches
Weight: 27 pounds
Coverage: Up to 1/4 acre
Max Slope: 45%
Obstacle Climbing: Up to 1.57 inches
Navigation: Full-Band RTK + VSLAM
Obstacle Avoidance: Dual-Camera AI Vision
Mapping: AI Auto-Mapping and App-Controlled Manual Mapping
App Control: Yes, via Roborock App
Anti-Theft: PIN code lockout, alarm, optional 4G module
Edge Precision: 1.2 inches (with optional cutting module)
When choosing a robotic lawn mower, consider your yard size and complexity. The RockNeo Q110H is ideal for up to 1/4 acre with slopes, trees, and obstacles. Wire-free setup saves installation time, but ensure your yard has clear boundaries for mapping. The dual navigation system is excellent for shaded areas, but if you have a very large lawn, look for a model with higher coverage.
For edge precision, the optional cutting module is recommended for a clean finish near borders. Anti-theft features are robust, but the 4G module adds cost. If you have pets or children, the AI obstacle avoidance provides peace of mind. Always check the app compatibility and consider the need for additional accessories based on your specific yard layout.
Pros
- Wire-free setup saves hours of burying perimeter wire
- Advanced dual navigation prevents lost signal under canopies and near fences
- Strong slope and obstacle handling with 4WD and active steering
- Wide cutting width and adjustable height for faster, customized mowing
- Comprehensive app controls and anti-theft features
Cons
- Premium price point may be too high for small, simple lawns
- No verified customer reviews yet, so long-term reliability is unproven
- Heavy 50-pound design requires ample storage space and may be difficult to move
The roborock RockMow X115H is a premium wire-free robotic lawn mower built for homeowners with challenging, mid-sized lawns up to 0.37 acre. It replaces buried perimeter wires with a combination of full-band RTK and quad-vision cameras, making it a strong choice for anyone who wants precise, hands-off mowing without the installation hassle.
Standout performance starts with the X115H's dual navigation. Full-band RTK maintains accurate positioning even near tall fences and dense canopies, while quad-vision AI adds visual awareness to avoid collisions and keep cutting lines consistent. The 4WD system with active steering and dynamic suspension handles severe slopes up to 80 percent and climbs over obstacles up to 3.15 inches, so it can manage rugged yards where many competitors struggle.
The mower's build is robust and thoughtfully engineered. Its 50-pound frame, wide 9.49-inch cutting deck, and adjustable cutting height between 1.57 and 3.54 inches offer a professional-grade finish. The multi-sensor obstacle avoidance system safely steers around people and pets, while the app provides detailed mapping, zone scheduling, and real-time progress tracking for a truly hands-off experience.
The most obvious trade-off is price, as this model sits at the high end of the robotic mower category. Additionally, with no verified customer reviews yet, its long-term reliability is still an open question. Buyers with very small, simple lawns may find the advanced features and cost hard to justify, and the heavy 50-pound unit requires ample storage space.
For homeowners with complex terrain, steep slopes, and a desire to eliminate wire-installation work, the roborock RockMow X115H is a compelling investment. Its navigation accuracy, climbing ability, and smart safety features make it one of the most capable wire-free robot mowers available. While the price is steep and data on durability is limited, the feature set delivers exactly what demanding users need.
Coverage: Up to 0.37 acre
Cutting Width: 9.49 inches
Cutting Height: 1.57 to 3.54 inches
Max Slope: 80 percent (38.7 degrees)
Navigation: Full-Band RTK plus Quad-Vision AI
Drive System: 4WD with Active Steering and Dynamic Suspension
Obstacle Avoidance: Multi-Sensor Fusion with 4 sensors
Dimensions: 25 x 11 x 18 inches
Weight: 50 pounds
Color: Dark Grey
Pros
- Exceptional traction on steep slopes and uneven terrain
- Wire-free setup with accurate LiDAR navigation
- Fast recharge time (45 minutes)
- Whisper-quiet operation suitable for any time of day
- Smart features including app control and security camera
Cons
- Higher upfront cost compared to basic robot mowers
- Optional trimmer module sold separately for tighter edges
- Coverage limited to 0.5 acre without additional units
The DREAME A3 AWD is a high-end robotic lawn mower that combines powerful all-wheel drive with advanced LiDAR and AI vision. It is designed for homeowners with challenging lawns featuring steep slopes, complex shapes, and obstacles. Unlike traditional mowers that require buried boundary wires, the A3 AWD maps your yard in minutes using 360-degree LiDAR and binocular AI, ensuring precise navigation even under heavy tree cover.
Standout features include its ability to handle slopes up to 80% and climb over obstacles up to 2.17 inches. This makes it suitable for properties with rolling hills or multi-level terrains. The 45-minute fast charge is a significant advantage, reducing downtime and allowing the mower to complete up to half an acre in a single day. Additionally, the ultra-quiet operation means you can schedule mowing at night without disturbing the peace.
Build quality is robust with a 26.4-pound chassis designed for durability. The included 4G module and HDR camera provide real-time monitoring and theft protection, adding security value. The Dreamehome app offers intuitive control, including custom mowing patterns and animal-friendly modes. However, the optional trimmer module is sold separately, which may be a minor inconvenience for those wanting the smallest possible edge gap.
One potential drawback is the price point, which is higher than many entry-level robot mowers. However, considering the advanced features and the elimination of monthly lawn care bills, it can be a cost-effective long-term investment. Also, the coverage area is rated up to 0.5 acre, so larger properties may need additional units.
Overall, the DREAME A3 AWD is an excellent choice for tech-savvy homeowners who prioritize a wire-free, high-performance mowing solution. It delivers professional-grade results with minimal effort, making weekends truly free for relaxation. If you have a challenging lawn and want top-tier technology, this mower is worth the investment.
Pros
- Excellent ventilation reduces heat buildup inside the shelter.
- Sturdy windproof frame with ground anchors provides stability in storms.
- Universal fit works with many popular robot mower brands.
- Easy to assemble and fold flat for storage.
- Waterproof and UV-resistant fabric offers long-lasting outdoor protection.
Cons
- No reviews yet, so real-world durability is unconfirmed.
- Small size may not accommodate larger robot mowers or those with tall accessories.
- Fabric may require periodic cleaning to maintain waterproofing.
The CNAINFC Robot Mower Garage is a purpose-built shelter designed to protect your robotic lawnmower and its charging station from the elements. It is ideal for owners of popular models like Segway Navimow, Mammotion LUBA, WORX Vision, and many others who want to extend the life of their equipment without building a permanent structure.
The standout feature is the 3D Cross-Ventilation System, which actively circulates air from front to back. This prevents heat buildup during hot weather and keeps the charging contacts dry, reducing the risk of corrosion. Additionally, the double UV-coated 600D Oxford fabric resists fading and cracking, ensuring the shelter looks good season after season.
Build quality is impressive for the price. The stainless steel frame is reinforced with lawn anchors and an anti-tip design, so the shelter stays put even in heavy wind and rain. The extra-large opening accommodates most mowers without scraping the radar or sensors, and the tool-free assembly means you can set it up in minutes.
One potential drawback is the lack of customer reviews, so long-term performance is not yet proven. Also, the small size may be tight for larger mowers or those with additional attachments. However, the foldable design makes off-season storage convenient.
Overall, the CNAINFC Robot Mower Garage offers a well-ventilated, windproof, and universal solution at a reasonable price. If you own a compatible mower and want reliable protection from sun and rain, this shelter is a smart investment.
Pros
- Exceptional slope handling up to 80% for challenging lawns.
- No need for boundary wires thanks to AI vision and RTK.
- Large 0.75 acre coverage with efficient dual-blade cutting.
- Smart multi-zone and obstacle recognition for versatile use.
- Anti-theft GPS tracking and full app control.
Cons
- Premium price point may not suit all budgets.
- Requires strong 4G signal for full remote features.
- No user reviews yet, so real-world reliability is unverified.
The Mammotion LUBA 2 AWD 3000HX is a revolutionary robotic lawn mower built for homeowners with challenging terrain. It combines all-wheel drive with advanced AI vision and RTK navigation, allowing it to handle slopes up to 80% and operate without perimeter wires. Perfect for 0.75 acre properties, this mower is designed for those who need robust performance on steep or uneven lawns.
Standout features include the UltraSense AI Vision system that ensures precise lawn recognition and zero-distance edge cutting, even under trees where satellite signals are weak. The RTK auto-mapping creates accurate boundaries, while the 4G connectivity allows remote monitoring and control. Its dual-blade design with a 15.8 inch cutting width delivers efficient mowing, covering up to 0.25 acre per charge with adjustable heights from 2.2 to 4.0 inches.
The build quality is solid, with a rugged chassis and powerful 165W motors that prevent getting stuck in thick grass or rough terrain. The mower can manage up to 30 different zones, including no-go areas like pools and flower beds. Intelligent obstacle avoidance recognizes over 200 objects, adapting its path to protect your landscape.
Potential drawbacks include a high price tag and reliance on a strong 4G signal for full functionality. Additionally, there are no verified user reviews yet, so long-term reliability is unknown. The mower's size (27.1 x 20.2 x 11.9 inches) may be bulky for storage.
Overall, the Mammotion LUBA 2 AWD 3000HX is a top choice for owners of steep, complex lawns who want a wire free, intelligent mowing solution. Its advanced navigation and robust traction set it apart, making lawn care effortless even in difficult conditions.
Pros
- Robust all-weather protection (rain, snow, UV, hail).
- Compatible with a wide range of robot mower brands.
- Secure installation with included ground anchors.
- Sleek, low-profile design that fits garden aesthetics.
- Easy to assemble and disassemble for seasonal storage.
Cons
- May be too small for some oversized mower models; check dimensions.
- Polycarbonate roof may scratch over time if not handled carefully.
- Limited color choice (only black).
The CNAINFC Robot Mower Garage is a practical and durable shelter designed to protect your robotic lawn mower and its charging station from the elements. It is ideal for homeowners who want to extend the life of their mower by keeping it safe from rain, snow, hail, intense sunlight, and debris. The garage is compatible with a vast array of popular mower brands, including Segway, Husqvarna, WORX, and many others, making it a versatile choice for most users.
Standout features include its heavy-duty steel frame and polycarbonate solid sheet roof, which provide robust all-weather protection. The garage is designed to prevent overheating and moisture damage, ensuring your mower runs efficiently year-round. Real-world performance is solid, with the included stainless steel ground anchors keeping the structure stable even in windy conditions, giving you peace of mind.
The design is clean and modern, with a sleek black roof that blends naturally into any garden setting. Assembly is straightforward using screw-joint connections, and the garage can be installed on lawn or hard ground. The side access allows your mower to easily enter for recharging or rain protection, maintaining a tidy outdoor space.
One potential drawback is that the large size may not accommodate all oversized mower models, so it is wise to check dimensions before purchase. The polycarbonate roof may also be prone to scratching if not handled with care. Additionally, the color is limited to black, which may not suit all preferences.
Overall, the CNAINFC Robot Mower Garage offers excellent value for its price, combining robust protection, easy installation, and a sleek design. It is a worthwhile investment for any robot mower owner looking to safeguard their equipment and enhance their lawn care routine.
Color: Black
Size: Large Size
Dimensions: 32 x 29 x 17 inches
Weight: 6.6 Pounds
Material: Steel frame, Polycarbonate (PC) solid sheet roof
Compatibility: Fits 99% of robot mowers (Lymow, Segway Navimow, Sunseeker, Mammotion LUBA, Mammotion YUKA, ANTHBOT, ECOVACS, MOVA, Greenworks, Husqvarna, DREAME, WORX)
Pros
- Wire-free setup saves time and eliminates the need for perimeter wire installations.
- Combines robot mower and grass trimmer in one kit, covering both mowing and edging tasks.
- Optical navigation performs well even in high-contrast lighting, ensuring efficient grass identification.
- Obstacle avoidance and magnetic strip virtual fence provide flexible control of mowing boundaries.
- Capable of climbing moderate slopes, making it suitable for varied small lawn layouts.
Cons
- Requires clearly defined lawn edges; the mower may leave the grass if edges are not well-maintained.
- Rated for up to 4000 sq ft but needs an additional battery charge to cover the full area in one session.
- No smartphone app or smart home integration limits automation and remote control options.
The LawnMaster OcuMow Robot Lawn Mower and Trimmer Combo Kit (B0D2L5PWRS) is designed for homeowners with small to medium yards (2000-4000 square feet). It stands out by eliminating the need for a buried perimeter wire using optical navigation technology. Instead, the mower uses a wide-angle, high-dynamic-range camera to identify grass and navigate your lawn efficiently. This makes setup as simple as placing the mower on the grass, pressing start, and letting it work.
Key standout features include its dual ultrasonic sensors for obstacle avoidance, detecting objects as small as 6 inches and redirecting the mower automatically. The included 33-foot magnetic strip allows you to create no-go zones without any power source or digging. Additionally, the combo kit comes with a cordless grass trimmer (10-inch cutting width) for edge work, providing a complete lawn maintenance solution. The mower can also climb slopes up to 35% (19 degrees), adding versatility.
In terms of design and build, the OcuMow sports a sturdy orange body with deep-tread wheels for grip on uneven terrain. The 24V MAX battery system (nominal 21.6V) powers both the mower and the trimmer, with two batteries included. The mower's runtime varies, and for full coverage of a 4000 sq ft lawn, an additional battery charge might be needed. The trimmer features an adjustable handle, auto line feed, and a pivoting head for precision edging.
However, there are a few drawbacks to consider. The mower requires a clearly defined lawn edge around the full perimeter; if edges are unkempt, the mower may drift off the grass. Also, the lack of a smartphone app means you cannot schedule mowing remotely or track the mower's progress. While the magnetic strip is a clever solution, it is limited to 33 feet, so larger no-go zones may require extra strips (sold separately). Finally, the product has no customer reviews yet, so real-world long-term reliability is unverified.
Verdict: The LawnMaster OcuMow combo kit offers a compelling, wire-free approach to robotic mowing for small lawns. Its included trimmer, optical navigation, and obstacle avoidance make it a solid choice for homeowners who want a simple, no-fuss setup. However, if you need smart features or have a lawn larger than 4000 sq ft, you may need to look elsewhere. For its price point and included tools, it provides good value for the target audience.
Buying Guide: What to Look for in a Robot Mower for Hills
Slope Capability and Drive System
The most critical factor for hilly lawns is the maximum slope rating. Look for models with at least 70% (35°) capability. All-wheel drive (AWD) systems provide superior traction on uneven terrain. Mammotion’s LUBA 2 AWD 3000HX climbs up to 80% slopes thanks to its 165 W four-wheel motors. Similarly, the DREAME A3 AWD handles 80% inclines with heavy-duty hub motors. Avoid rear-wheel-drive mowers on steep grades; they often lose grip.
Navigation and Mapping Technology
On hills, GPS signals can be blocked by trees or terrain. Choose a mower with RTK (Real-Time Kinematic) satellite navigation plus visual SLAM or LiDAR for under-tree accuracy. Mammotion’s UltraSense AI Vision combined with RTK ensures seamless positioning even in shade. The WORX Vision Cloud uses cloud-based RTK without a local antenna. For larger properties, see our best Mammotion mowers for half an acre.
Obstacle Avoidance and Safety
A mower on a hill must detect and avoid rocks, roots, and garden furniture. AI vision systems like Mammotion’s UltraSense recognize over 200 objects and choose appropriate responses. The WORX Vision AI processes 10 trillion operations per second to understand obstacles. Ultrasonic sensors on models like the LawnMaster OcuMow add an extra layer. Always verify that the mower can handle your yard’s specific hazards.
Coverage Area and Battery Life
Hilly lawns require more energy, so battery capacity matters. The Mammotion LUBA 2 covers up to 0.75 acre per charge with its dual-blade design. The Roborock RockMow X115H manages 0.37 acre with 4WD. For smaller slopes, the LawnMaster OcuMow handles 2,600 sq. ft. Consider fast charging; the DREAME A3 recharges in 45 minutes. For larger yards, check our top picks for one acre.
Final Thoughts
For the best Mammotion robot lawn mower for hilly lawns, the Mammotion LUBA 2 AWD 3000HX Robot Lawn Mower stands out with its 80% slope climbing, RTK+AI navigation, and 0.75-acre coverage. If you prefer a more budget-friendly option with strong hill performance, the (Upgraded) DREAME A3 AWD 1000 LiDAR Robot Lawn offers similar 80% grade capability and fast charging. Both models eliminate the need for perimeter wires and deliver professional-grade results on challenging terrain.
Related Guides
- Top WORX Mowers for Steep Slopes
- Robot Mower for Hilly Yard Black Friday Deals 2026
- DREAME A3000 LiDAR PRO for Hills
Frequently Asked Questions
Can Mammotion robot mowers handle very steep hills?
Yes, models like the Mammotion LUBA 2 AWD are rated for slopes up to 80% (38°). Their four-wheel drive and terrain-adaptive chassis provide excellent traction. Always check the slope rating of the specific model against your lawn’s steepest sections.
Do I need perimeter wires for Mammotion mowers on hills?
No, Mammotion mowers use RTK satellite navigation and AI vision to map your lawn without boundary wires. This is especially beneficial on hills where burying wire is difficult. The system automatically detects lawn edges and no-go zones.
How does the Mammotion LUBA 2 navigate under trees on a slope?
The LUBA 2 combines RTK with UltraSense AI Vision using V-SLAM sensor fusion. When satellite signals weaken under tree cover, the visual system seamlessly takes over to maintain precise positioning. This ensures continuous coverage even on shaded hillsides.
What is the best Mammotion robot lawn mower for a 0.5-acre hilly lawn?
For half an acre with hills, the Mammotion LUBA 2 AWD 3000HX is ideal. It covers up to 0.75 acre per charge and climbs 80% slopes. Its dual-blade cutting deck handles thick grass efficiently. For a smaller budget, consider the Roborock RockMow X115H, which covers 0.37 acre and handles 80% slopes.
