Binary package “xflip” in ubuntu lunar
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.