By Evan Ackerman
Nothing too gadgety about this, I’ll admit, but it’s a neat little effect… Flip the pages of this book, and a rainbow will appear above it. Each of the 36 pages has an image of the spectrum on a black background which creates the illusion. Looks like it was just an art project, but you can make your own in 10 minutes with an inkjet and some staples. Vid after the jump.