% This picture represents the cartesian plain
% (C) Thiago Brevidelli
\begin{tikzpicture}
    \draw (0, 0) node[left]{$\mathbb{R}^2$} -- 
          (2, 0) -- 
          (3, 1) -- 
          (1, 1) -- cycle;
\end{tikzpicture}

