Seems like a good way to teach about sub-pixel rendering and HighDPI. Perhaps abstract so the screen is an addressable pixel (so as not to break the world), divide each virtual pixel into, say, a 4x4 submatrix (or even 8x8, 16x16, etc), and have new (prefixed?) functions that work on the sub-pixels (which ideally map 1:1 to actual screen pixels). For back compat, address pixels with two offets..one in the virtual grid, and one for the sub pixel.