julia> a = [1 2]; 1x2 Array{Int64,2}: 1 2 julia> b = [3 4]; 1x2 Array{Int64,2}: 3 4 julia> [a b] 1x4 Array{Int64,2}: 1 2 3 4 julia> [a; b] 2x2 Array{Int64,2}: 1 2 3 4 julia> [a' b'] 2x2 Array{Int64,2}: 1 3 2 4