HellMood has updated his 16 byte paint program for MS-DOS, making this already insane sizecoding prod even more incredible. It now has an exit function (by moving the cursor to the left border), a visible cursor, and can draw thicker lines. Check it out here. (Hint: try all possible combinations of left/right/middle mouse button for different colors.)
The asm source is included again, so you can see for yourself how this magic works.