I don't normally trail new ebooks but I'm really excited about this one. Creating Hybrid Image Illusions in GIMP takes you through the process of creating a new form of illusion that can be used to create dual reality effects, forces that involve two people seeing different words on the same piece of paper, and so on.
Here's an example:

It clearly says TREAT in ghostly writing. Now step away from the computer screen a few metres and look again. Weird, or what?
Based on work done at MIT in the 1990s, hybrid images are a completely new class of illusion. They're not simply two images overlaid.
What could you do with the ability to create your own hybrid images? Amazing things, that's what. In this upcoming ebook, I explain the full process of creating your own hybrid images using free, open source software. That's right, FREE!