Included below is a short video of the process and its astounding results. When you watch it, you literally may not believe your eyes:
Step 1: Materials Needed
1) One sheet of 8.5"x11" paper
2) Another sheet of paper at least 5"x6" in size
3) Black pen
4) Brown crayon or colored pencil
5) Orange crayon or colored pencil (any color lighter than brown will work fine)
8) Red Magic Marker
Step 2: The Creation (Part 1)
**Edit: The tabletop dimensions should be 4.25" x 2" (not 4" x 2" as shown in the image notes)
Step 3: The Creation (Part 2)
These edges are actually a huge part of what "sells" this illusion because they manipulate our eyes into processing the dimensions of the actual tabletops incorrectly. You can see from the photo below that there is NO WAY that these two tabletops look like they are the same in size. Part of that is the camera angle, but most of it is the illusion itself!
Using your black pen and your ruler, darken the lines as shown in the photo below. This enhances the 3D effect and provides for a sense of depth. It's all about the perspective in the end.
Step 4: The Creation (Part 3)
Using your brown crayon or colored pencil, color the entire right table(legs and all). Then color every part of the left table brown except for the tabletop.
Using your orange crayon or colored pencil, color the left tabletop.
Step 5: The Proof!!
Using your necessary materials and the other piece of paper, measure and cut out a parallelogram (2"x4.25"). With your red marker, make a .25" border within the edges of its perimeter. This will make the proof more obvious and clear.
Place the cutout on the left tabletop to prove that it is the same size as the tabletop itself. Then move the cutout over and place it on the right tabletop. Amazingly, it is now proven that both tabletops are exactly the same size!
If you decide to take on this project, prepare yourself for mass amounts of scrutiny and insults about your sanity (or lackthereof). Just don't lose your proof cutout! :)