3D Cube

\usepackage{tikz-3dplot}
\tdplotsetmaincoords{70}{110}

\begin{tikzpicture}[tdplot_main_coords, scale=2]
  \draw[thick] (0,0,0) -- (1,0,0) -- (1,1,0) -- (0,1,0) -- cycle;
  \draw[thick] (0,0,1) -- (1,0,1) -- (1,1,1) -- (0,1,1) -- cycle;
  \draw[thick] (0,0,0) -- (0,0,1);
  \draw[thick] (1,0,0) -- (1,0,1);
  \draw[thick] (1,1,0) -- (1,1,1);
  \draw[dashed] (0,1,0) -- (0,1,1);
\end{tikzpicture}