Build a combinatorial matrix from two vectors
It's called Cartesian product and you can do that easily:

Here's one way:

y = [10 30 50 70]

x = [10 30 50]

[X,Y] = meshgrid(y,x);
result = [Y(:) X(:)];


Result:

10   10
30   10
50   10
10   30
30   30
50   30
10   50
30   50
50   50
10   70
30   70
50   70