The seven alternating sign matrices of size 3.
Created in LaTeX by the following code:

\documentclass{article}
\thispagestyle{empty}
\usepackage{amsmath}
\begin{document}
\[
 \begin{bmatrix}
  1 &amp; 0 &amp; 0\\
  0 &amp; 1 &amp; 0\\
  0 &amp; 0 &amp; 1
 \end{bmatrix}
 \qquad
 \begin{bmatrix}
  1 &amp; 0 &amp; 0\\
  0 &amp; 0 &amp; 1\\
  0 &amp; 1 &amp; 0
 \end{bmatrix}
\]
\[
 \begin{bmatrix}
  0 &amp; 1 &amp; 0\\
  1 &amp; 0 &amp; 0\\
  0 &amp; 0 &amp; 1
 \end{bmatrix}
 \qquad
 \begin{bmatrix}
  0 &amp;  1 &amp; 0\\
  1 &amp; -1 &amp; 1\\
  0 &amp;  1 &amp; 0
 \end{bmatrix}
 \qquad
 \begin{bmatrix}
  0 &amp; 1 &amp; 0\\
  0 &amp; 0 &amp; 1\\
  1 &amp; 0 &amp; 0
 \end{bmatrix}
\]
\[
 \begin{bmatrix}
  0 &amp; 0 &amp; 1\\
  1 &amp; 0 &amp; 0\\
  0 &amp; 1 &amp; 0
 \end{bmatrix}
 \qquad
 \begin{bmatrix}
  0 &amp; 0 &amp; 1\\
  0 &amp; 1 &amp; 0\\
  1 &amp; 0 &amp; 0
 \end{bmatrix}
\]
\end{document}
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