A question: how many people here can/can't do the Magic Eye thing?

I usually can, though it's a bit of an effort. I can only ever do it by focussing too far away (wall-eyed), not too close (cross-eyed).

No matter how hard I've tried, I just can't make it work. I suspect that it's because my eyes are different focal lengths -- I'm (only slightly) short-sighted in my right eye, but my left-eye is normal.

I've only ever tried Magic Eye pictures with my glasses on, not least because I can barely see that far in my right eye without them on -- so in that situation my vision's probably been equalled out. But in my parents' house, my bedroom wallpaper had a very short pattern-repeat, and waking up in the morning a foot away from it I'd sometimes focus on that at entirely the wrong distance due to Magic Eye effects, so I don't think having two different prescriptions is in itself a problem.

Peter