to pentagon repeat 5 [ fd 100 rt 72 ] end
That jogged my memory to a cool sample Logo Interpreter written by Adam Granicz in less than 400 lines, posted on HubFS back in 2006. The code didn’t run straight away due to some subtle changes in the language, but after some worthwhile coercion I was able to resurrect the code, which I have attached.
canvas 300 300
to pentagon :x repeat 5 [ fd :x rt 72 ]
canvas 400 500
spiral :x repeat :x [fd 4 lt * repcount 1.1]
Logo.fsx (19.71 kb)