I just adore doing optical illusions, and kids really seem to love them too. This is a great one that students can easily experience success with (especially if you use my template!)
Let me start by talking about the template. I debated for a while if I would give them one, wondering if I was giving them too much of an advantage or not. I decided to make a template with little ticks along the side, so they still have to use a ruler to make the lines, but it takes out the measuring aspect of it. So many kids struggle with that kind of thing, and I don't know if it's fair to make that an aspect of this art project. As it was, some of them even had trouble joining up the lines from the template. Anyway, I've uploaded the template for download here. Please let me know how it goes if you use it!
First, have students trace the lines on the template. I reminded them to trace LIGHTLY, as they will need to erase the lines in the circle afterwards. I tried to draw up how to do the circles, because I don't really know how to explain it well in words.
I gave the students the option to add a T to the tender of the circle. This just breaks the middle section up a bit, and it also makes it easier for them to color in the checkerboard pattern .
Once they are done this part, they can start the fun part - coloring them in! I showed them how to use gradient coloring techniques to add to the illusion, having the gradient get lighter as it got closer to the circles. Every second square was colored with Sharpie or markers.Some students mapped it out first, and some just went for it.
I advised them to color the background first, then do the circles. It seemed to make it easier on them.