Calibration "Cube"

I made a relatively low volume calibration shape to allow measuring how far off printed parts will wind up. I use this to adjust scaling factors to get more accurate prints - you'll want to use whatever settings you plan to print your normal parts in.
All the measurable lengths are in increments of 5mm, and you probably won't be off by more than 5mm, but here are the measurements you might want to check:
The X and Y legs should be 100mm long with widths of 10mm, and 5mm height.
The hole should be 15mm square.
The tower should be 10mm x 10mm x 25mm.
The holes are 1.5mm, but if you're over-extruding a bit, they'll be almost closed. The holes are 80mm apart.

Comments and critique are welcome.