code challenge

Do something graphical in 50 lines of readable normally formatted code, don't count whitespace or lines with a single character(like a closing brace).

something graphical
* = $7c
ora $a2
and #$3f
tay
sbc $a1
eor $a2
ora $a2
and #$7f
sta $d400,y
sta $cfd7,y
bvc $7c

If you really want 50 lines just nop the rest...