That's awesome. Thanks for sharing. I think I will do some upgrades.
The rounded rectangle code has the following explanation:
roundrectangle <x-start> <y-start> <x-end> <y-end> <x-rounding pixels> <y-rounding pixels>
Every item has a co-ordinate starting from 0,0 at top right of the image unless otherwise coded. You have to do a bit of trial and error with the font and font sizing if you decide to change away from the default font.