Espyo | Poké Ball myth busted - Sonic Adventure @srb2Espyo | Uploaded December 2010 | Updated October 2024, 9 hours ago.
Some time back, I had made a video about a sighting of a Poké Ball in one of Final Egg's textures. youtube.com/watch?v=EuF65SBqUC0 There was some debate as to whether that truly was a reference to the Pokémon games, or just a coincidence. There is one way to find out: if the texture also appears on the original Sonic Adventure, then it's not a reference, because Sega wouldn't want to make a reference about a Nintendo franchise. Sega and Nintendo were at war during Sonic Adventure's making, but not during Sonic Adventure DX'.
I recorded a 'wrong tunnel' in Sonic Adventure, and the result...

EDIT: Looks like there is also a Poké Ball of sorts in the helipads in Speed Highway, as pointed out by Pinkolol16. I can confirm that they exist in the DC version and the DX remake, although the latter flipped the whole helipad texture 90º for some reason. imgur.com/a/uDTVV