The SNES controller (American).
The Super Nintendo Entertainment System controller had a rounded dog-bone like design and added two more face buttons to the NES Controller, "X" and "Y", arranging the four in a diamond formation. Another addition was the "L" and "R" shoulder buttons, which have been imitated by most controllers since.
There is a slight variation in the Japanese and European version of the controller, where the A, B, Y and X buttons are all convex-curved and each one has a distinct color (A was red, B was yellow, X was blue, and Y was green). For the American SNES, the A and B buttons were colored purple, whereas the Y and X buttons were lavender and concave-curved.