raycasting isn't used for polygons
ray casting is where you have a grid, and every cell on the grid either has a wall, or lacks a wall (it can be extended to give different heights to the walls).  Now, take a line with 96 evenly spaced segments (1 for each pixel the lcd is wide), and a point behind the line (the eye).  Draw a line from the eye, through the center of each of the 96 segments, and see where the closest intersection of that line and a cell that contains a wall is.  Now, from that distance, you calculate how tall the wall should look, and draw that in the vertical center of the screen.  Checking the ray for collisions is complicated, since you can't just test every time the line travels one unit (you could miss walls that way if the unit mark happens to not be in that cell), so you have to use DDA (digital differential analysis), where you check for a hit every time the x or y position of the line is a whole number.

like what?  that's basically what DAA is.  Maybe if I ever feel like learning Axe I could port my 3D engine.

I updated my to-do list.  I've pretty much finished everything I thought would be "essential" for the beta release, so I think I might just halt the new commands for a little bit and just focus on writing the user's guide.  Sunday I plan to release the next version: 0.2.0 but this time, it won't just be on omnimaga.  I'll be releasing it on ticalc.org as well as several other calculator forums to expand interest in the project.  So this will be a very big release.

That on top of the different dimensions for sprites and the DrawShape command.

(I'm going to keep bugging you about that.)

What's the command?
Or will it be something the Parser itself picks up?

Actually, that would be kind of useful.  So most likely, yes. I guess that's what ^r is for