\begin{tikzpicture} \tikzstyle{point}=[thick,draw=black,cross out,inner sep=0pt,minimum width=4pt,minimum height=4pt] \node (a)[point,label={[label distance=0cm]180:$e_0$}] at (0,0) {}; \node (b)[point,label={[label distance=0cm]0:$e_1$}] at (2,0) {}; \node (c)[point,label={[label distance=0cm]0:$e_2$}] at (1,2) {}; \node (d)[point,label={[label distance=0cm]0:$e_3$}] at (1,0.7) {}; \draw (a.center) -- (b.center) -- (c.center) -- cycle; \draw[dashed] (a.center) -- (d.center) -- (b.center); \draw[dashed] (d.center) -- (c.center); \end{tikzpicture}