In response to a question about how to make a box with rounded corners, here is a way:
http://www.glowscript.org/#/user/Bruce_Sherwood/folder/Pub/program/RoundedBox
When viewing the program, click "Edit this program" to see the code. I guess this is a candidate for adding to VPython.
Of course if you run this in VPython 7 you need to change the first line to be "from vpython import *".