\documentclass[tikz]{standalone}

\usepackage{tikz}        % Pretty drawings
\usepackage{tikz-3dplot} % More dimensions!
\usetikzlibrary{
	external,
	calc,
	positioning,
	backgrounds,
	decorations.pathreplacing,
	calligraphy,
	decorations.markings,
	matrix,
	arrows,
	patterns,
}
\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfsetlayers{background,main,foreground}

\begin{document}
\include{tikz/multipath-sketch.tex}
\end{document}