Combining {a,N} and {b,N} trees to form {a,b,N} tree

I have two data sets(floating point numbers) which I want to combine

One data set is 11 branches of N = 100 and the other data set is 4 branches of N = 100
What I want to do is add the numbers together in all combinations so I have 11 branches with 4 branches each with N = 100 data points.

I’ve tried various combinations of simplify, graft and flip matrix but i’m not getting what I want.

Can anyone point me in the right direction for this?

Thanks

Look into list manipulation; Cross Product sounds like what you are after