/usr/share/k3d/lsystem/willow-tree.ls is in k3d-data 0.8.0.3-3build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 | # --- L-System Parser/Mutator --- Lj Lapre ----------------------------------
13
10
100
#
c(12)FFFFFFFFFF>(1)&(1)A
#
A=!(.75)t(.9)FB>(94)B>(132)B
B=[&"t(.9)!(.75)FL[|zL]$AL[|zL]]
#
L=[~c(8)f(40)|{+(30)f(80)-(120)f(80)-(120)f(80)}]
@
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