Update: I updated the stereo photography post yet again (you can't write a weblog without embracing writing as an iterative process). Taking a closer look at how I screwed up the placement of the images for viewing, I found the photo taken from the left-most vantage point needs to go on the right side and vice versa. That way, when you cross your eyes, the left eye sees the photo taken from the left and the right eye sees the photo taken from the right.
Earlier post: This is embarrassing. After advising all of you to "keep track of which is the left most photo and right most photo" in my post about stereoscopic photography, I completely ignored that with my examples. Except for the Lisa/Wiggum pair, each of the examples had the left and right images transposed. This means that unless you were standing on your head, you either couldn't see the effect or saw it in a kind of reverse 3-D with the far objects near and the near objects far.
Anyway, you should take another look if you failed to see the effect before...they are all much better now. Thanks to David for catching this.