https://en.wikipedia.org/wiki/Dragon_curve

the dragon curve set of rules has the same structure as the arrowhead of Sierpinski.

Once you know the grammar, it does not take a long time to adapt into a Dragon curve.

you can find the rule set on internet. you can find a lot of rule sets...

variables : F G

constants : + −

start : F

rules : (F → F+G), (G → F-G)

angle : 90°

Here, F and G both mean "draw forward", + means "turn left by angle", and − means "turn right by angle".

in my model F=1 G=2 +=3 -=4

1. Open the 3dxml of Arrowhead of Sierpinski in my previous Tuto

2. modify the rules (1 → 132), (2 → 142)

3. modify the angle to 90deg

final 3dxml