In the 1960s, biologist Michael Land showed that each scallop eye uses a mirror to focus light into images, while most other eyes use lenses (SN: 5/28/16, p. 22). MIRROR, MIRROR Cryo-electron microscopy images show that the mirror in each scallop eye is made of tiny, perfectly square crystal tiles (shown) that together build a reflective mosaic. For one thing, the guanine crystals that build the scallop’s eye mirror are perfectly square, says study coauthor Benjamin Palmer, a biologist at the Weizmann Institute of Science in Rehovot, Israel.