Am I being thick, or are cassette teeth not symmetrical? My shiny new *gold* T-Rex has teeth that are more rounded at once side than the other – like a worn out chainring.

I always thought the teeth started symmetrical, nice and round, then as they wore out got elongated at one side. This T-Rex appears to come with pre-worn teeth. Have I missed something?

They aren’t symmetrical. One side provides a positive ‘hook’, while the trailing side allows release. Different shape innit.
(I’m just a casual bystander)