Peter Szinek <peter / rubyrailways.com> wrote/schrieb <45B9E90C.7010106 / rubyrailways.com>: > Also it is maybe more intuitive (for me at least) to write: > > first_ary.cartprod second_ary How should my example then look like? It can't be [1,2].cartprod([3,4,5]).cartprod([6,7,8]), because then the result would be different: [[[1, 3], 6], [[1, 3], 7], [[1, 3], 8], [[1, 4], 6], [[1, 4], 7], [[1, 4], 8], [[1, 5], 6], [[1, 5], 7], [[1, 5], 8], [[2, 3], 6], [[2, 3], 7], [[2, 3], 8], [[2, 4], 6], [[2, 4], 7], [[2, 4], 8], [[2, 5], 6], [[2, 5], 7], [[2, 5], 8]] Do you appreciate [1,2].cartprod([3,4,5], [6,7,8]) ? Regards Thomas