Snake
Your Own Past, In the Way
Eat, grow longer, and touch neither the wall nor yourself. Every fifth fruit brings a big bonus fruit on a short countdown, worth more the sooner you reach it; it does not make you longer. Apart from the wall, the only obstacle is the trail you have already made, so every fruit makes the next harder to reach.
The Path That Cannot Cross Itself
A line that grows one step at a time and is forbidden from touching its earlier self has a name in physics: a self-avoiding walk. It is the standard model of a long molecule in solution. A polymer chain can bend whichever way it likes except through itself, and that single restriction is enough to change how much space the molecule occupies, how it responds to being stretched, and how two chains in the same liquid get in each other's way. Counting self-avoiding walks exactly is unsolved past modest lengths. You are playing inside the constraint that makes the problem hard.
How to play
- Arrow keys turn and you cannot reverse into your own neck; 1 to 9 set the speed before a game.
- Run along the wall early and keep the middle open for later.
- Each fruit adds a segment, shrinking the safe area.
- A long snake needs a plan for getting out of wherever it just went in; fill the field and you win.
