Binary package “xflip” in ubuntu lucid

programs to mirror-image or melt your display

 Flip your (or your "xhost +" using friend's) screen on either the vertical
 or horizontal axis or melt away the graphics on your display. Both commands,
 named xflip and meltdown, have a -planes option to independently act on
 individual bit planes. This version now comes with a new -oblic option which
 flips horizontally and vertically simultaneously.