Using a single letter (or short) variable name works well most of the time but has one problem: the variable can leak. It's easy to forget to write the del statement. Imagine a block statement that had the effect of deleting any variables initialized in the block. That is (using the with keyword in this example but there are other choices): x = foo() with: y = x + 1 x = y + 2 is equivalent to: x = foo() y = x + 1 x = y + 2 del y or after optimization: x = (foo() + 1) + 2 [Obviously more useful with real code but this is sufficiently illustrative. Also I imagine someone might say it's just foo() + 3 but I don't know the type of foo().] --- Bruce -- --- Bruce Check out my puzzle book and get it free here: http://J.mp/ingToConclusionsFree (available on iOS)