Why do we cut sandwiches into triangles?

* Structural integrity. Triangles are self-supporting, which means that they don't need to be held together with toothpicks or skewers. This makes them ideal for sandwiches that will be eaten on the go.

* Stability. Triangles are more stable than other shapes, such as rectangles. This means that they are less likely to fall apart when you take a bite.

* Even distribution. Triangles allow the filling to be evenly distributed throughout the sandwich. This makes sure you don't end up with a bite that's all filling and no sandwich.

* Aesthetics. Many people find triangles to be the most aesthetically pleasing shape for sandwiches. They are also a classic shape, which may be why they are so commonly used.

There are a few other shapes that sandwiches are sometimes cut into, such as rectangles, squares, and ovals. However, triangles are the most popular shape for sandwiches, and for the reasons listed above.