Title text:
This discovery was key to his demonstration of regular/goofy symmetry violation, which won him gold in the theory portion of the X Games.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3264/
First ollie 720 over a gap: https://youtu.be/1fmfsZ3Ye-g
First ollie 720 on vert: https://youtu.be/dGScJcp-Y3c