L = M || N
This command joins NCMatrices vertically.
i1 : A = QQ{a,b,c,d} o1 = A o1 : NCPolynomialRing
i2 : M = ncMatrix {{a,b,c,d},{b,c,d,a}} o2 = | a b c d | | b c d a | o2 : NCMatrix
i3 : N = M || 2*M || -3*M o3 = | a b c d | | b c d a | | 2*a 2*b 2*c 2*d | | 2*b 2*c 2*d 2*a | | -3*a -3*b -3*c -3*d | | -3*b -3*c -3*d -3*a | o3 : NCMatrix