The method is very simple:

Make 4 lines
Type SPIN 43 IT
ROTATE 89 IT
GROWBY 1% 1000 IT

(the code becomes:
growby 3% 1000 [
rotate 89 [
spin 34 [
color red [line -234 124 -13 8]
color yellow [line 301 134 -18 16]
color lightgreen [line -281 -131 -20 16]
color blue [line 258 -92 -24 14]
]
]
]