%Converted to svg with pdf2svg
\documentclass[tikz]{standalone}
\usetikzlibrary{decorations.markings}

\newcommand{\arrowIn}{
	\tikz \draw[ultra thick,-stealth] (-1pt,0) -- (1pt,0);
}

\begin{document}
	\begin{tikzpicture}
		% Left part
		\draw[draw=black,fill=black] (-1,0) circle (0.05cm) node[above] {\large $x$};
		
		\draw[ultra thick, black] (0,0) -- node[above] {\large  $x(\tau)$} (2,0);
		
		\draw[ultra thick, black] (2,0) -- (3.5,1.5);
		
		\draw[ultra thick, black] (2,0) -- (3.5,-1.5);
		
		% Right part
		\draw[ultra thick, black] (5.5,-1) -- (5.5,1) node[above] {\large $X(\sigma)$};
		
		\draw[ultra thick, red, line cap=round] (6.5,1) --  node[above, black] {\large $X(\sigma,\tau)$} (8.5,1)  node[
		sloped,
		pos=0.5,
		allow upside down]{\arrowIn};
		
		\draw[ultra thick, red, line cap=round] (8.5,1) -- (10,2.5) node[
		sloped,
		pos=0.5,
		allow upside down]{\arrowIn};
		
		\draw[ultra thick, green, line cap=round] (10,1.5) -- (8.5,0) node[
		sloped,
		pos=0.5,
		allow upside down]{\arrowIn};x
		
		\draw[ultra thick, green, line cap=round] (8.5,0) -- (10,-1.5) node[
		sloped,
		pos=0.5,
		allow upside down]{\arrowIn};
		
		\draw[ultra thick, blue, line cap=round] (8.5,-1) --  node[
		sloped,
		pos=0.5,
		allow upside down]{\arrowIn} (6.5,-1) ;
		
		\draw[ultra thick, blue, line cap=round] (10,-2.5) -- (8.5,-1) node[
		sloped,
		pos=0.5,
		allow upside down]{\arrowIn};
		
		%Black lines
		\draw[ultra thick, black, line cap=rect] (6.5,-1) -- (6.5,1);
		
		\draw[ultra thick, black, line cap=rect] (10,2.5) -- (10,1.5);
		
		\draw[ultra thick, black, line cap=rect] (10,-2.5) -- (10,-1.5);
		
		%Boxes
		\draw[ultra thick, black] (-2,-3) rectangle (4.5,3);
		
		\draw[ultra thick, black] (4.5,-3) rectangle (11,3);
	\end{tikzpicture}
\end{document}