36 Jordan blocks

A $k\times k$ Jordan block with eigenvalue $\lambda\in{\bf C}$ is the matrix

J_{k}(\lambda)=\begin{bmatrix}\lambda&1&0&\dots&0\\ 0&\lambda&1&0&\dots\\ \vdots&0&\ddots&\ddots&0\\ \vdots&\ddots&0&\ddots&1\\ 0&0&\dots&0&\lambda\end{bmatrix}

J_{1}(\lambda)=[\lambda],\quad J_{2}(\lambda)=\begin{bmatrix}\lambda&1\\ 0&\lambda\end{bmatrix},

J_{3}(\lambda)=\begin{bmatrix}\lambda&1&0\\ 0&\lambda&1\\ 0&0&\lambda\end{bmatrix}