An interesting handheld variation of this Snack involves gluing the two mirrors to a block of foam rubber, which acts as a spacer. Mirrors 6 × 6 inches (15 × 15 cm) work well for this portable version, but mirror size is not crucial. The foam should separate the mirrors by 2 or 3 inches (5 to 8 cm).
An even simpler handheld version uses pieces of sponge as spacers, with rubber bands holding the mirrors together. Use a soft sponge—the cheap ones used for washing cars work well. One or two holes can be drilled into the mirror. See the diagram below (click to enlarge).
Squeeze the foam or sponge so the mirrors are not quite parallel to each other, and you’ll see a pattern of images that curves off into infinity!
As you can see in the diagram, another version of this Snack involves making two holes in one of the mirrors—one for each eye. Try it!