Review : Marking time

Tatsuo Miyajima’s Big Time installations employ light-emitting diodes
re-counting time from 1 to 9 and a Zen blank. Numerate viewers exhaust the
structure in milliseconds. But where else can you watch a population of several
dozen turtle-robots interacting with each other and the walls, and their
emergent patterns? Do. Hayward Gallery, London SE1, until 17 August.