Round Bologna - Square Bread
Q. Why do they make bologna circular if bread is square? ~ Oscar M.
A. – Glad you asked - Bologna is actually a sausage. It's made by packing an emulsified meat mixture (one that's extremely similar to hot dogs, in fact)
into a casing or tube. Bologna is served in slices, but you can also buy a whole one, usually in the deli meat case. It's a long cylinder of meat.
The casing or tubing are mostly made of an edible collagen, or inedible cellulose or plastic. The red ring found on some bolognas is plastic, which you need to remove before you make a sandwich.
It is possible to make square shaped deli meats. Some are really pates (cooked in a pan rather than a casing), or chopped up pieces. These can be square when sliced. (It's also where those perfectly circular slices of turkey come from, made in a circular mold.) But bologna is traditionally made in casings, so that's how you get it, round!