› Hi, Bot Games
Loss Mountain Walk the robot downhill in the fog. That's how AI learns.
A 3D hill where height is how wrong a model is, and the robot can only feel the slope under its feet. Pick a step size and walk it down: too small and you run out of steps, too big and you fly off. 5 hills, from a simple bowl to a real one built from Weight Pond's pond 3. Walking downhill like this is how AI learns.
1–2 players · ~10–14 + parents · ~15 min · one screen
What this teaches
Play in your browser
Free, no login. Nothing you do in the game leaves your device. Works on a laptop, tablet, or phone.
Good to know
Plays in any browser on a phone, tablet or Chromebook. No account, and nothing you do in the game leaves your device. The one-page guide prints on plain paper and has an unplugged version for a class without screens.
How to play
The robot is on a hill in the fog. Height is how wrong a model is, so the lowest point is the best answer. The robot can only feel the slope under its feet. Pick a step size, step downhill, and find the bottom before you run out of steps. Five hills. The last one is a real model's error.
How to play
- The arrow at the robot's feet points downhill. Press Step to take one step that way, or 10 steps to take ten.
- The step size slider sets how far each step goes. Each hill has a step budget.
- When the run ends, the fog lifts and you see the whole hill, your path, and the real bottom.
- Hill 3 has a Try another start button. Hill 4 has a Momentum switch.
What the mountain teaches
- Training an AI means lowering its error. Picture every setting of its weights as a map, and the error as the height.
- The model can't see the whole map. It feels the slope where it is and steps downhill. This is called gradient descent.
- Step size is the learning rate: too small is slow, too big overshoots.
- You can get stuck in a valley that isn't the deepest. Momentum and fresh starts help.
No screens? Play it unplugged
- No screens? Build a pillow mountain under a blanket. One player is blindfolded and may only feel the slope under one hand.
- Before each move, a teammate calls a step size: one hand-width, two, or four. Count how many moves it takes to reach the lowest spot.
- Try it again with two dips in the blanket. Did the blindfolded player find the deeper one?
Downloads
Grown-up guide
Plain paper · 1 page · 8.5 × 11
How to play, what it teaches, what every step size does on each hill, and a no-screens version with a pillow mountain.
Guide preview
One page for grown-ups and classrooms: what it teaches, plus a version with no screens.
On a phone, open the PDF in a new tab — in-page previews are unreliable in mobile Safari.
Played Loss Mountain?
Playtest notes — round length, rule confusion, print quality, teach-back moments — help us tune the game.
Send playtest feedback →Want more than card games?
Want facilitator-ready printables the day they drop, plus the full Activities library for grades 6–12? Activities Pass — 14 days free, then $5/month or $39/year. Browser games like this one stay free either way.
Start 14-day free trial →Homeschooling? Print tips & FAQ · Want the screen-free activity library? Free printables · Start 14-day free trial