Distinct image

Had this very distinct image in my mind tonight, but couldn't figure out where it was from. Something to do with moving forwards (eg. x direction), then flipping upside down (eg. rotate about x-axis), then continuing the flip to be right side up again. Something fairly difficult to do for beginners. Seemed to think it was something to do with swimming. But why would I rotate upside down then continue rotating after some point? It's not that flippy-turn thing some people do at the end. So, maybe it was something I'd seen on TV or in a video game. Maybe needed to rotate a jet or spacecraft upside down to go through something, then continue? No, not that. But it had to be something where you (or the object) has more width/length than height. So you'd be lying on your stomach maybe. If you were standing up it wouldn't make sense... unless you ran forwards onto a spear that impaled you through the belly, then rotated about it to stand on your hands, then continue rotating to be right side up as you run off the other end (handle) of the spear. (That was an awesome image!) Finally figured it out... it's from surfing! I think for passing through a wave as you're lying on the board swimming out into the ocean. Anyways, once I realised it, it makes me want to go try surfing again (not to try that manoeuver, just to stand and surf).

Also was considering sailing lessons... something we actually can do in calgary! Anyone else interested?