I think you need to reconsider the meanings of the "if" statements inside your loops. I haven't looked at the scrip to see what the GetIndex function is doing, but I have to assume it is basically the equivalent of "mmap.plotNum(xx,yy)". If so, then what the "if" statement immediately after it doing is making the function return false if you ware within 25% of the map width or height of an edge. I assume the function is used to allow the placement of a wormhole. If so, then that first "if" makes it impossible for you to place one within a very wide border around the edge of the map. The second "if" condition is insisting that every single plot in the very wide area must have the same feature on it. I seriously doubt that you will find any region measuring half the side of the map in both directions where every single plot has the same feature. Thus it will effectively always return false. If the thing calling this loops until it returns true, then this would make it an infinite loop. My suggestions, based on some assumptions about what you really want: In the first "if" make it a "continue" instead of a "return False" so that the loops will keep looping, just skipping the rest of the statements in the loop when the plot is off the map (if that's what i = -1 means) For the second "if" it is less clear what you want. I am guessing that what you really want is to find out if there is already some feature (a wormhole, I expect) in the area. In that case, change the condition from "!=" to "==", so that you will bail out if you find the feature instead of bailing out if you don't find the feature.