Hi there! Quick introduction: I'm fairly new to programming (I've taken a few introductory programming courses in college, but nothing language-specific), and have chosen to learn Python for practicality and fun. In an effort to apply what I learn, I'm building a game piece by piece, testing new programming concepts as I acquire them. The game I'm working on is a simple ASCII, turn-based "pseudo-tower defense/roguelike", and though it's very early in the development phase, I'm having a lot of fun. Now, my question is this: I want to create a global resource (in this case, oxygen) that begins at 100%, and then is reduced by a certain value (typically 1-3%) per turn the player makes. How the heck would I do that? Please know, I don't need actual code or anything (though pseudo-code would be appreciated). I'm really just more curious about how such a thing would be implemented. Actually creating it is still a ways down the road, and at this point, I'm just interested in the logic of it. So far, I've been able to construct the logic for most of the game, but this is just puzzling to me. I'd really love to just have a discussion about this particular aspect of programming, and would really appreciate any guidance the Indie Gamer community could offer. Thanks in advance!