A diagram of a wood burning pizza oven is a better way of getting a clear understanding of what you would want to build or you would want your pizzas oven to look like. There are numerous types of wood fired pizza oven and it mainly depends on the materials you have and the purpose of the pizza oven. For home based pizza oven, the igloo dome shaped pizza oven will be the best option. On the other hand, the barrel vault pizza oven is best suited for commercial uses.
The diagram of an igloo dome shaped pizza will seem round in its basic shape while that of a barrel pizza oven will be rectangular oriented.
Further information: How to build a pizza oven and Build a wood burning clay pizza oven