See my Assessment Ideas, and download all of the files for free at: http://www.thingiverse.com/thing:1878943

I have 2cm interlocking blocks that come with the curriculum materials for PLTW, but I wanted something with larger and more varied dimensions for the students to measure. I also wanted the object to cause students to use the different tools that are on the caliper.

So, I created this:

See my assessment ideas, and download all of the files for free at: http://www.thingiverse.com/thing:1878943

I printed several of them out on an Ultimaker 2 and I use them to assess my students' caliper skills or give them extra practice.