photography is foreign to most, but I've had an affection for it for many
years. These are just a few samples, set in "cross viewing" style.
To see these you need to focus your eyes beyond them, as if on something
behind them. You see double when doing that, and the trick is to get the
two inner images to overlap together. Once you've done that you'll be in
for a surprise, as instead of a "flat" picture, everything will
be at varying distances, as if you are actually there.