In 1984 Christopher Langton created a two-dimensional cellular automaton capable of self-reproduction. The reproducing pattern consists of a loop containing genetic information inside. The genetic information is a sequence of cells that flows outside the loop through its arm, which eventually become another loop. Some part of the genetic information is encoded to cause three left turns of the loop, which then closes or dies and does not reproduce anymore. There is no size limit for the colony of loops reproduced in an unbounded two-dimensional space. This system is considered to be a good example of artificial self-reproduction.