I wanted to create a new gameplay aspect: Supplies What I actually want is that whenever a certain unit comes out of a certain area (own territory + supply aura's) his stats a reduced (whether that would be lower health, lower battle stats or a degeneration of it's stats, deciding that would require playtesting) I had in mind of coding some stuff doing the following: Selecting own territory + supply aura area and invert the selection. Check if the unit is in the latter selected area and if so apply actions. I think I need some code from the Territory decay and the aura part, correct? Can anyone help me with the start? (Since I've got no idea of how this stuff works in 0 A.D.)