The Joystick Range Test Shows A Square Instead Of A Circle, Is My Stick Broken?

This trace looks alarming but is usually harmless.

Each stick reports two separate values: X from -1 to 1 and Y from -1 to 1. If the controller passes those through without any shaping, pushing the stick into a diagonal can give full X and full Y at the same time, which plots outside the circle. Rotate around the edge and you draw a rounded square. Many first-party controllers process the values so the edge reads as a circle, which is what your friend's controller is doing.

So squareness is mostly a firmware choice, not damage. The practical effect is in the diagonals: if a game uses the raw values, moving diagonally can be up to about 1.41 times faster than moving straight, because both axes are at full. Most modern games normalise stick input themselves and you will never notice. Some older games and emulators do not.

What would point to a real fault is different: a trace that is lopsided, flattened on one side, or stops short of the edge in some direction. That suggests a stick that is worn, damaged or badly calibrated.

If you want a rounder output, check the pad's software for a circularity or square to circle option, or use Steam Input's outer deadzone settings for games that need it.