To themeperks, the stereo pairs are presented two ways for both types of free-viewing. The top pair, with the "X" in the corner, is posted with the L and R images transposed for cross-eyed viewing. The bottom pair, with the "P" in the corner, is presented in parallel format for literally more straightforward viewing, like the Magic Eye images. So free-viewers are covered either way. No need to do any extra work, it's already done for ya!

These 3-D quartets are fascinating, but - alas! - they are lost on me since I am blind in one eye. I've tried a sort of beat zen "what is the perspective of one eye crossing" but it hasn't worked. I'm not even getting 1.5-D out of it. Oh, well. Fortunately, most of the rest of the Shorpy world is getting a kick out of them, so I will enjoy them vicariously with my fellow Shorpyites.

Alas, seeing with only one eye, any 3-D is impossible to me. (I tried and I tried with these red and green glasses, but it never worked.

Haha I told my husband about Susie Susie Susie Susie and promised to show it to him so he could see her float past the sparkly tree on her trike. But then I forgot to do that, so today when I saw this one I took my laptop right to him and made him look. He couldn't do it. I watched him trying to get loose enough for the 3D to pop in, and his eyes looked SO funny. In my opinion he gave up too easily. Oh well. More for us.

The lower pair is for eyes not crossed (aka "blank stare"). Once you are able to do one, the other one will look odd. I think most people can do cross-eye. I can only do the other one (probably because my brain got used to "Magic Eye" books). It's rare to be able to do both. In any event, I'm glad you are enjoying these.

It's really true that once you learn how to "free-view" 3D photos like that, you never forget how. Once my eyes adjusted properly, it really was amazing how it worked. I hope to see more here on Shorpy — they're fun!

I really wasn’t getting it until I read JennyPennifer’s comment about the 3D shot of Susie, then this one. You just have to relax and cross your eyes and look at the top pair, then out it pops! The key, as JennyPenn says, is not overthinking it. So if crossing your eyes alone isn’t enough, then you’ve also got to let your brain go slack, get into a real stupid place, let your mouth hang open, and see if that helps. It did for me.

Yep, works like a charm! That cymbal is practically brushing the tip of my nose. I believe the wing nut (atop the cymbal stand, not me) is a trifle loose. These 3D things make me giddy.

You can tell, because it looks like he is embedded in the wall and the shelf is in front of the stick. If you copy them and swap them (flipping the pair won't fix it) then it's perfect.

"At least he's holding his sticks right."