Double T 

2 things

1)
a classic string-substitution part that makes it easy to make patterns
3 L 2 R
forward 3 Length-units and turn Left
forward 2 units and turn Right
length = scale

2)
CORNER FIX
added "tightenCorners" to fix ugly zigzag 90-degree-corner-gaps
you can toggle the fix by switching the contacts on top