Broken Hello World LCD
A small (128 RGB x 160) LCD panel with an extremely odd rendition of a blue square, red circle, green hollow triangle, and the text "Hello, world."
Images like this caused a small amount of hair loss and general frustration before determining that I was trying to debug an 8-bit 8080-like interface to a panel that was actually jumpered (I cut the wrong trace) to be a 16-bit 6800-like interface. It is actually amazing that it worked this well. The square, circle, triangle, and text are all in the right places. They are just wrong in details like color, and which pixels are actually lit.
This is a color transflective STN LCD with an LED backlight.
The text and figures were drawn by Micrium's μC/GUI running in an embedded system. The device driver still has bugs, however.
When the 16-bit interface issue was identified, we were able to get the expected display without much trouble.