\form#0:\[ minLevel \leq level < maxLevel \]
\form#1:\[ \Large \left \{ \begin{array}{r c l l l l l} x' & = & (a \times x) & + & (b \times y) & + & tx \\ y' & = & (c \times x) & + & (d \times y) & + & ty \end{array} \right . \]
