\begin{tikzpicture} % draw the D-brane \draw (0cm, 0cm) -- (5cm, -1cm) -- (6cm, 3cm) -- (1.5cm, 4cm) node[anchor=south west] {$D_{(t)}$} -- cycle; % draw a triad of axis \draw[thick, ->] (3cm, 1cm) -- (2.7cm, 0.1cm) node[anchor=east] {$X^1_{(t)}$}; \draw[thick, ->] (3cm, 1cm) -- (5cm, 0.6cm) node[anchor=south] {$X^2_{(t)}$}; \draw[thick, ->] (3cm, 1cm) -- (3cm, 2.75cm) node[anchor=east] {$X^3_{(t)}$}; \end{tikzpicture} % vim: ft=tex