Conway’s Game of Life, implemented in Conway’s Game of Life.
The OTCA metapixel is a 2048 × 2048 period 35328 unit cell that was constructed by Brice Due between the autumn of 2005 and the spring of 2006. It has many advantages over the previous-known unit cells such as the p5760 unit Life cell and deep cell, including the ability to emulate any Life-like cellular automaton and the fact that, when zoomed out, the ON and OFF cells are easy to distinguish (the ON version of the cell is shown to the right and the OFF version of the cell is shown below). (LifeWiki)
See also: More views of the metapixel