After some searching, I picked the following image and inserted it in Photoshop CS5, where I started building my piece:
For the centres of the circles, I used the word 'lost', giving it a radial blur effect and creating a couple of rotating duplicates, with a stroke applied to every other layer for differentiation. Notice that the colours are derived from my reference image.
Then, I started creating the rest of the circles' 'swirls' using question marks. One unit consisted two marks, one of which was upside-down and reflected;
which, in turn, was copied and rotated to create one 'loop':
The loop was then copied and scaled to create the other ones and hence complete the circle:
The circle was then copied to create the other four circles in the corners, and a path was drawn and used to create masks for them, so that they appear to be behind the central 'main' circle.
The final step was to remove the reference layer, leaving us with the result:
And there you have my 'typoptical' illusion! Hope you enjoyed it!