crayon simulation based on this paper
AzWHHdDj1kY6wP4e.mp4
NOTE if the crayon stops drawing try resetting the tip (B M or L on qt version or T on sdl version)
as of rn
in qt and sdl version:
- C clears canvas
 - number keys 1 thru 0 change colors
 - set the mode with (D)raw, (S)mudge, and (E)rase
 - U to undo/redo one stroke
 
in the qt version:
- change size/reset the crayon tip with (B)ig, (M)edium, and (L)ittle
 - change paper color with (R)ed, (G)reen, (W)hite, (I) black and (Q) blue
 
in the sdl version:
- reset the crayon tip with T
 
