Optical Illusions Power Point Presentation- 2nd-6th Grade

I shared a very cool power point presentation to the Second-Sixth Graders.  I would like to post the entire slideshow using google docs, however it is "macro-encrypted," which means it is protected from any kind of modifications.  I had to omit the third slide while I presented the slideshow to the students because of it's visual content.  I would like to share, however, one of the slides that the students liked the most: