latex - How to add symbols on edges to say they are same length? -

there edges having same length. want add little symbol on in picture:

how do? thanks.

 \begin{tikzpicture}         \coordinate (base1) @ (0,0);   \coordinate (base2) @ (4,0);   \coordinate (base3) @ (5,2);   \coordinate (toppt) @ (2,5);    \draw [draw=black, every edge/.append style={draw=black, dashed}]   (base1) -- (base2) --(base3)    (base3) edge (base1);    \draw [draw=black, every edge/.append style={draw=black, dashed}]   (toppt) -- (base1)    (toppt) -- (base2)    (toppt) -- (base3);   \end{tikzpicture} 

you'll need tikz decoration library (both decorations , decorations.markings):

\begin{tikzpicture}         \coordinate (base1) @ (0,0);   \coordinate (base2) @ (4,0);   \coordinate (base3) @ (5,2);   \coordinate (toppt) @ (2,5);    \draw [draw, every edge/.append style={draw, dashed}]   (base1) -- (base2) -- (base3)    (base3) edge (base1);    \draw [draw]   (toppt) -- (base1)    (toppt) -- (base2)   (toppt) -- (base3);   \draw [draw,decoration={markings, mark=at position .5  {\node[transform shape] {$\parallel$};}}]   (toppt) edge[decorate] (base1)    (toppt) edge[decorate] (base2)   (toppt) edge[decorate] (base3); \end{tikzpicture}