[Izzy Dunne]

If there are two dice, wouldn't the that depend on what combination equals seven on top?

No, if there's a 6 on top then there's a 1 on the bottom.

If there's a 5 on top, there's a 2 on the bottom.

If they add up to 7 on top, they add up to 7 on the bottom, too.

[Greysard]

No, if there's a 6 on top then there's a 1 on the bottom. If there's a 5 on top, there's a 2 on the bottom.

Is there any natural law why that would be so? I can make a cube with any number on any side. Two cubes don't even have to be identically marked.

Disclaimer: I haven't seen those cubes for many decades.