Neat! I will show this to a young person I know who’s just getting into programming on his RaspPi.
‘Turtle Mode’ is quite ingenious … memories of LOGO in my youth. Have you considered making a package that could parse this and render into a native window (GOOS=linux or win32) somehow so these programs could also run the same way offline?
A playground is for very basic things. For Raspberry Pi consider using LiteIDE wich is a complete IDE for Golang (yes, you can do cross compiling). Se here how to install.