Printer Calibration Cubes

After a couple failed attempts to print parts the are supposed to be mated together (they didn't fit), I realized that I don't fully understand how much error my printer has in each axis. So I designed these cubes which can be used to come up with an error profile for your printer.

For each print setting you want to test (speed, number of shells, layer height, etc), print this out, and use a caliper to take **5** measurements on each of the 3 pieces and compare to the expected sizes. Measure:

X-inner (hole) width
X-outer (peg) width
Y-inner (hole) width
Y-outer (peg) width
Z height

I expect that if you tell the printer to print a cube with X-axis size S, the actual printed size, T, will have both constant error, c (like 0.28 mm), and multiplicative error, m (like 4.6%). In otherwords:

T = m*S + c

Therefore, you technically only need two pieces to get two (S,T) pairs you can plug in and solve for m and c. I print three, because I want to do the calculation