Had fun with this for a couple minutes. Would definitely be cool to see what this becomes.

A couple things I noticed:

Underlining and placing the description of the command on the same line as the command made me totally glance over the actual command. I typed "Make box" two or three times before I saw there was an example, and then finally I saw the syntax.

Another nice thing would be if there were some defaults, especially for the initial x/y values.

A question would be, how exactly are joints supposed to work? Sometimes they seem very rigid, other times it almost bends.