Cursor left/right/up/down to navigate within 16x16 block world. Next trick is to draw walls at the calculated positions using the images from https://scratch.mit.edu/projects/159332081/ After that works, I guess we move on to two-point perspective, and using transformation matrixes for the viewing angle.
xy mapping of floor coords to screen coords extracted from @Wes64's https://scratch.mit.edu/projects/41468626/ (2 very critical lines!) I might change the perspective calculation for the one in https://scratch.mit.edu/projects/157841571/
