mat_mul(matA=[[1, 2, 3], [4, 5, 6], [7, 8, 9]], matB=[[10, 11, 12], [13, 14, 15], [16, 17, 18]])
mat_mul(matA=[[19, 20], [21, 22]], matB=[[23, 24], [25, 26]])
mat_mul(matA=[[27, 28, 29, 30], [31, 32, 33, 34]], matB=[[35, 36, 37, 38], [39, 40, 41, 42]])
mat_mul(matA=[[43, 44], [45, 46]], matB=[[47, 48], [49, 50]])