% This picture represents the relationshipt between the real, ordinal and
% surreal numbers
% (C) Thiago Brevidelli
\begin{tikzpicture}
  % The reals
  \draw (0,0) circle (1)
  (-1.5,0) node{$\mathbb{R}$};

  % The ordinals
  \draw (-1,0) circle (1)
  (0.5,0) node{$\mathbf{ON}$};

  % The surreals (+ natural numbers)
  \draw (-2.5, 1.5) rectangle (1.5,-1.5)
  (-0.5,0) node{$\mathbb{N}$}
  (1.5,-1.5) node[right]{$\mathbf{No}$};
\end{tikzpicture}