In fact the best way to eat pizza is as a sandwich. Not just folded, but if you get two pizzas with three toppings each, or a half and half pizza, then take two different slices and place one upside down on another, you now have a pizza sandwich with 6 different toppings, but still the proper meat/cheese/sauce ratio. Gamechanger.
Funnily I am sure there is a thesis somewhere by disgruntled sandwich fans who define 3d vectors which pass through the side showing its not true.
Its funny imagining the horror on their faces when they realize that there are vectors on the original sandwich that don't pass through bread -> filling -> bread.