How to construct a new matrix using existent ones



I have two matrix a:n*m and b:n*k, and I want to construct a new
matrix using a and b : [a b]: n*(m+k). How can I do in Maxima.

Thanks in advance!

-- 
Yours sincerely,
Jie Liu

graduate student,
State Key Laboratory of Industry Control Technology
Department of Control Science and Engineering,
Zhejiang University, China