## Boundary

A division between two regions. Physicists frequently analyze only a part of a larger system, so that they do not need to keep track of everything. This usually simplifies the analysis, but requires an understanding of what happens at the boundary. Interesting computer simulations usually require a boundary.

## Inspiration

The fault, dear Brutus,
Is not in our stars,
But in ourselves...

Julius Caesar
(I, ii, 140–141)