This set of test prints is designed to assist you in the calibration of build platforms. These prints attempt to balance time and plastic used with getting decent results. In short, it should be a more efficient method.
There are two sets of calibration prints included here. The first set is for build plate leveling. These are the flat squares. They are intended to print above the build platform thumbscrews. Please see below for details.
The second set is a set of concentric cylinders. These are intended to help you adjust belt tension on your MakerBot Replicator 2. Again, please see below for details.
Update 4/5/13: Added circle calibration print. After having circles that came out as ellipsoids, I created these as a simple test of belt tightness.