I use the name for the list L, P for the point, I refer to other variables as given. Typically, the local variables used in a number less than 1000 lines of code, I use only one letter. If I have several identical within the meaning of variables, such as two points, I add a number, for example P1, P2 ... Most often, I use the letters that are easy to press with your left hand - right more often occupied by the mouse.