The original PADDY stack was just a simple vertical spacer that had a proportional setting and if you set it to 10% of screen height or 10% of screen width, you could create a spacer that occupied more space on large screens and less space on smaller screens. What made it a more useful tool was that you could see it in a layout in RW Edit mode, and with the additional option to display the spacer settings in the Edit window, it turned out to be far more useful than expected. You could see what it did without needing to click on the stack, and then examine the stacks settings. It is one of those proverbial tins that says SPACER on the tin. Also once you got the initial spacing sorted out you could copy the stack throughout your site to maintain the same spacing. Will’s S4S Utility stack is much more clever when used as a spacer stack.