Something is undefined for some devices when using 3d with the processingjs library

Nobody has claimed this yet.

When I made this: https://www.khanacademy.org/computer-programming/3d-maze-game/5316019273465856 lots of people told me they were getting an error. E.g. "Why can't I play? It just says undefined!"
At first I assumed the webgl stuff was complaining that they didn't have a good enough gpu. However I tested the maze game out on a variety of devices, and found one that threw the error, then wrote this: https://www.khanacademy.org/computer-programming/my-first-threejs-app/5606329430966272 which also uses webgl but through a different library. And yet the three.js app works on the device that won't play the maze game, sooo.. that sort of poked a hole in my first theory. So maybe the error is fixable?

Start by reproducing the "undefined" error from the linked 3d maze game on the affected device, then compare it with the linked three.js example, which works there. Trace the live editor's ProcessingJS/WebGL path; the issue names no repository files or tests. Done means the maze game works on the affected device without the undefined error.

Written by the indexing model from the issue text.