[rablackburn]

The flipping-between is a great hack -- as you said your eyes (really, brain) just do the work for you.

I learnt about it in Japan where proof-readers and editors would (or do) quickly lift a top page up and down to spot mistakes with kanji (pictographs). And sure enough, even from a page of dense script the dissonance of the error really does pop out at you.

I likewise tucked that little trick into my belt -- it comes in useful anytime you're trying to manually spot a pattern across complex data. This technique has the same "vibe" as FFTs to me: it's just neat feeling like you're getting computation from the universe for free.

Solar PV in a similar category: free electrons if you can arrange the magic rocks just right :)

[Terretta]

If you put two proofs side by side, you can view from the right distance then uncross or cross your eyes like a stereogram till they converge, which makes differences shimmer.

Instant "spot the difference" solve.

// Long time in print and digital agency

[kayge]

And once you have the hang of this technique, congratulations! You can now enjoy those 3D "Magic Eye" images that stumped a significant portion of the population back in the 90s :)

e.g. https://old.reddit.com/r/woahdude/comments/1lxqd0l/the_most_...

[Terretta]

Right, “like a stereogram”!

https://en.wikipedia.org/wiki/Autostereogram

[donbrae]

I use ScreenFloat[0] in a similar way to catch differences between GUI settings, like the cPanel PHP extensions selector, which has tons of checkboxes. Position a screenshot of settings for site A over the settings for site B, adjust the transparency, and any differences will jump out.

[0] https://eternalstorms.at/ScreenFloat/

[Garrett_Mack]

Whoa that's fascinating! Thank you so much for sharing this, I never would've thought of it that way at all.