sentences:  By the 15th century, some girih patterns were no longer periodic, and may have been constructed using girih tiles.This method is based on a set of five tiles with lines drawn on them; when used to tile the plane with no gaps, the lines on the tiles form a girih pattern.It is not yet known when girih tiles were first used for architectural decoration instead of compass and straightedge, but it was probably at the start of the 13th century.