The vertcat(M1,M2) function creates a new array with the rows of M1 on top of the rows of M2.

All input arrays must have the same number of columns and dimensions.

$\mathrm{with}\left(\mathrm{MTM}\right)\:$

$\mathrm{M1}≔\mathrm{Matrix}\left(3\,2\,'\mathrm{fill}'=1\right)\:$

$\mathrm{M2}≔\mathrm{Matrix}\left(2\,2\,'\mathrm{fill}'=2\right)\:$

$\mathrm{vertcat}\left(\mathrm{M1}\,\mathrm{M2}\right)$

$\left[\begin{array}{cc}1& 1\\ 1& 1\\ 1& 1\\ 2& 2\\ 2& 2\end{array}\right]$