iStereogram HD

Price: $.99 (or free version w/ads)
Grade Recommendation: 3rd and up
Subject: Art
Specific Skill: Optical Illusions
Levels: N/A
Players: N/A
For iPad, iPod, or Both: iPad

Stereograms are optical illusions that initially look like static you'd see on a television screen. When you look at them a certain way, 3D images seem to 'pop' out at you. To see stereograms, the user has to look beyond the picture. If done so correctly, an image - within the image - will appear.

I've only used this app once with students and probably never will again. However, I'm leaving it on the iPads because I won't mind if they stumble across it on their own and will probably explain its purpose when they do. While I can see the images contained within stereograms quite easily (by crossing, then slowly uncrossing my eyes), I realized I couldn't explain to my students how to also do so. I wasn't comfortable teaching them how to cross their eyes! :)

I'm filing this app under the subject of art. Perhaps an art teacher could incorporate the app into a lesson or unit on optical illusions.

The free version has ads running across the top of the screen. But their presence doesn't distract from each of the 150+ stereograms contained in the app.