The Square Four is a motorcycle produced by Ariel between 1931 and 1959 and was designed by Edward Turner, who devised the Square Four engine in 1928. The Ariel Square 4 was the first four cylinder "sporting" motorcycle. The original Ariel Square Four was created by legendary engine designer, Edward Turner in 1930 and it soon became a much loved classic. Nickname the Squariel Lightweight, Classic fit, Double-needle sleeve and bottom hem