# Problem 349: Langton's ant
An ant moves on a regular grid of squares that are coloured either black
or white. The ant is always oriented in one of the cardinal directions
(left, right, up or down) and moves from square to adjacent square
according to the following rules: - if it is on a black square, it flips
the color of the square to white, rotates 90 degrees counterclockwise
and moves forward one square. - if it is on a white square, it flips the
color of the square to black, rotates 90 degrees clockwise and moves
forward one square. Starting with a grid that is entirely white, how
many squares are black after 1018 moves of the ant?