Little calibration set

As for many others, I started with the 40x40x40mm made by Bre http://www.thingiverse.com/thing:477
But to make quicker test and waste less plastic I rapidly designed a 30x30x10mm (and then the others)

I know they are among the easiest things to make in every software, but sometimes it's faster to just download it (I checked Thingiverse before designing them, months ago). And we still see people looking for that, thus I'm sharing these blocks :)