Yea and you can only select an adjacent spot so that also limits combinations.

You can actually select spots not adjacent to the current one.

Consider the "spots" labeled in rows from left to right as 1 2 3, 4 5 6, and 7 8 9.

If I start at 1, I can go to 2, 4, 5, 6, and 8 directly. Also, if I have used all spots except 1 and 9, I can go to 1 then directly to 9.

Yep, and the fact that the above calculation doesn't even allow for combinations greater than four... Overall not a reliable number :)

My Galaxy S4 seems to only allow one direction for each node.

You can in fact only select each pad once.