large hanging lens creates upside-down images of distant objects
and right-side-up images of nearby objects. The upside-down images
can be located by using a piece of white paper as a screen. The
right-side-up images are harder to find.
Standing a few feet back from the lens and looking through it
at objects on the other side, visitors will see distant objects
upside-down; nearby objects will appear right-side-up.