Virtually every aspect of a gamepad is patented and fiercely protected. The Achilles' Heel of the Xbox 360 gamepad is the wobbly directional disc. Nintendo use

Virtually every aspect of a gamepad is patented and fiercely protected. The Achilles' Heel of the Xbox 360 gamepad is the wobbly directional disc. Nintendo uses a sensible cross, Sony's is in segments. Microsoft had to find an alternative which didn't involve paying a fee to a competitor for each unit sold.