The elbow joint is 3d circular, much like a character in s 3d game
Move you wrist around each axis!
The sparkler. Make in o in dark when holding a sparkler firework. This is rotation around the the z axis
Turn the Ferris wheel. (Using the knob on the reel). This is rotation around x.
Run around the flag, at the olympics. This is rotation around y
Now you have grasped what she meant!