Cartesian XYZ Model

Demonstrating things in a Three-Dimensional space is some of the most difficult to do, especially with precision and within a mathematical framework. No matter how many times I looked at an isometric approximation of a 3D Cartesian space, I couldn't perfectly visualize it. For this reason, I created this for my 3D Printing for Teachers class in my graduate work for education. Just recently polishing it, this should be the final version of my standing XYZ Cartesian model, pending feedback from others. There are a few ways to use this device:

1) Place the xy-plane square hole over the z-axis base peg, then slot the z-axis top peg into the combined peg hole. From here, the evenly spaced measurements can be used to give a more precise visual 3D space.
2) Before slotting the z-axis top peg into the combined square hole, tie a thin piece of string around the peg, and then tie the other end to a bead or similar "dot"-like object, to simulate a point in the Cartesian Space. This can also b