You posted an example of just that this last week. Unlike hashes, arrays are ordered, so they can fit this bill. A typical Pythagorean triple might be @a = (2,3,7);. There has to be an origin: @o=(0,0,0);. One way this differs from typical mathematical treatments is that the indices begin with zero, but all that requires is that you be consistent. One thing you can't have are strings in your vector so this: @d=(8,7,dog); will never be a vector. Hope this helps.