Phototaxis is a new take on the classic cellphone game snake, with controls reimagined for the Apple Watch's Digital Crown.

•• Requires Apple Watch to play ••

Phototaxis, noun: The instinctual movement of an organism towards light.

Spin your watch's Digital Crown to move the light around the game board. Your snake will dutifully follow. Eat rings to score points and grow. But be careful: the more you eat, the longer you get, and the longer you get, the easier it is to trap yourself.