Hmm, seems your first 12" is short by about 1 full cm, odd, as I can see that there is little to no error or missing material, although I suspect missing material is probably what's to blame here. Still, odd..
I like the thought process with this entry.
I dont know how you did the got them suspended above the bg, but I like it when a photo makes me think "how did they do that"?
Lol, you broke this ruler specifically for the challenge?
Nice idea and I like the colors, but the centimeters are betraying you here a little bit. I think the rulers are all the same size, but the fact that the first and second go to 30 and 60, but the third goes to 91 is affecting my perception of the symmetry. Its a minor nitpick though