A cheeseburger has a patty and cheese (which we will refer to as a layer), bun, lettuce,tomato, onion (this has been a debate, but overall non-relevant so I will include

it) and secret sauce. A double-double has two patties and two slices of cheese (or two layers),bun, lettuce, tomato, onion, and secret sauce. A 3x3 (called a three-by-three or a triple-triple) has three patties and three slices of cheese (or three layers), bun, lettuce, tomato,onion, and secret sauce. 1. What are the differences between a cheeseburger and a Double-Double?