Without redundant code:<p><pre><code> \documentclass[border=3pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{lindenmayersystems}
\begin{document}
\begin{tikzpicture}[line width=1pt, rounded corners=4pt,
l-system={
rule set={X -> X+YF+,Y->-FX-Y},
axiom=FX, angle=90, order=11, step=10pt
}
]
\foreach \c/\r in {green/0, red/90, blue/180, orange/270}
\draw[\c, rotate=\r] l-system;
\end{tikzpicture}
\end{document}</code></pre>