[Suggestion] Vertical Grid

There has been plenty of times flying and or swimming have been present in a session, a vertical axis grid or at least some kind of elevation marker would be awesome for tokens and proper visualization of Flying/swimming pieces. I am no suggesting a "3D" grid, but rather a grid that can be opened and used when necessary relative to the token, kind of like a second map for elevation.

Adding something like this would be great. Right now I use the numbers on a token icon to indicate how many squares above or below ground level something is. For example there is a wing icon on the token I just put a '3' on it if it is 3 squares higher than the rest of the board.

The last time I had anyone changing vertical axis was in a Star Wars Saga game... I had a player, henceforth known as "Jetpack Steve" that would continuously fly everywhere, even during stealth missions. He was in flight so often I made a little "Up" arrow to represent the use of the jetpack.