Draw the hills, dips and ramps yourself, then watch a sled rider careen down your sketch under real gravity and momentum.
You build the course by drawing lines. The rider rides whatever you sketch, accelerating downhill, carrying momentum over jumps, and slowing on the climbs. Place a flag or goal and craft a track that carries the rider there, decorative scenery costs nothing, so doodle freely.
Slope Sketch recreates Line Rider, built by Bostjan Cadez in 2006 as a student project with no score, no goal and no way to win.
You draw a line and a small sledder runs down it under gravity and momentum; that is the entire program. Because it was a toy rather than a game, people turned it into a medium — elaborate hand-drawn courses, choreographed to music, shared as videos. It is one of the clearest cases of an audience deciding what a piece of software was for, and it works because the physics are simple enough to predict and fussy enough to be worth mastering.
Slope Sketch is an original free browser physics toy in the draw-your-own-track tradition, with a daily puzzle and an open sandbox. No download needed.