Canned pasta is a by-product of most cultures who discover the many uses of preserving food. It isn't a DIRECT result of said technology, and one will usually be hard-pressed to find an entry for "the direct industrial evolution of canned beefaroni in cheese sauce" in the average encyclopedia, but in many cultures with developed urban areas (such as America, Japan, Britain, and China) the average supermarket can be found stocked with a variety of canned goods. While canned vegetables or preserved fruits in syrup are the most common type of canned food, that is not the topic of this writing. Onward, then, to the ravioli!
Ravioli, canned, is manufactured by several food companies in the United States, one of the best-known of these being Chef Boyardee. Originally of Italian origin, ravioli was quickly embraced as an easy-to-reheat meal in American homes. It is most often presented as a square piece of pasta with a cheerful dagged edge, a top piece of pasta, also square and shaped somewhat like the shell of a turtle, and a filling of either cheese or minced meat (usually beef). Ravioli can also be circular, and while the average size is roughly an inch in diameter it isn't very difficult to purchase "mini-ravioli" of only a centimeter (or less) in width, or even to find "mega-ravioli" twice the size of the average pasta form.
Ravioli, when pre-cooked and ready to ship, is packed loosely into a metal can at the factory and covered in a red tomato-based sauce. Said sauce usually has a meat or cheese flavoring added to it. Some brands of ravioli have actual chunks of meat in their sauces, others have herbs and spices added. While some cans have brightly-colored labels affixed to them, occasionally with games printed on the back, others are more taciturn. Pictures of the can's contents are nigh universal in the world of canned pasta.
Because it has already been cooked, and the canning process protects its contents from many bacteria, canned ravioli is actually safe to eat directly from the can itself. While this could easily be seen as revolting, it is quite a welcome feature for a hungry child without access to a microwave or a college student with a term paper due. When eating ravioli from the can, a fork or spoon is equally useful, depending on the actual size of the ravioli. In the case of the diner actually wanting WARM food, dumping the can into a ceramic container and heating for a minute or two with a stove or microwave will produce a tasty meal best eaten with a fork and napkin.