|Original "Autistic Pride" symbol/ribbon|
The alternatives all boil down to taking an infinity symbol, then having a linear rainbow gradient run across it... That's nothing at all like how a ribbon or even how the infinity symbol works (it's not flat!), and I'm kind of picky about things like that, so it wasn't quite enough.
Last night, while writing a comment at Slate's Dear Prudence column, where a woman had written for advice on ensuring her newly-identified-AS daughter gets to enjoy Thanksgiving, I felt frustrated at the inability to find an appropriate avatar. I liked the spectrum Moebius Strip one that Oddizm made many years ago, but few people would realize it wasn't just a pretty picture
Just blurring it didn't look quite right even with the edges sharp. I tried using it as a guide for the Path Tool (which I'd then Stroke with a rainbow), but I never did master Paths and soon gave up. I ran through all of the available filters that looked remotely applicable, but didn't get results I liked. Eventually, I tried Gaussian Blur + the hand-controlled Smudge tool to mix colors.
A while of working later, I had an acceptable (not gorgeous, I'm not an artist!) ribbon in both original proportions & a more condensed version that fits in a square, plus had one square version with text (shown). I'm picturing the basic image here, and clicking on it will bring you to a gallery of the other variants/sizes. Feel free to use it as an avatar online, to edit it, or whatever you want.