Cuttlefish over a Sandy Reef

The cuttlefish has one of the oddest eyes in the sea, with a pupil shaped like a W. Inside its body sits the cuttlebone, the chalky oval often clipped to a pet bird's cage. The one in this cuttlefish jigsaw puzzle has turned sandy and mottled to match a shallow reef. It does that with color cells in its skin that change in a fraction of a second, even though cuttlefish are thought to be colorblind.