code/__HELPERS/levels.dm 
| /proc/is_valid_z_level | |
|---|---|
| /proc/is_on_a_planet | Checks if the passed non-area atom is on a "planet". |
| /proc/get_linked_z_angle | Gets the angle between two linked z-levels. Returns an angle (in degrees) if the z-levels are crosslinked/neighbors, or null if they are not. |