=== LOL Path ===

A path in LOL is written in the form:

  a ~= b

To access the end-points of the path `a` and `b`:

  (a ~= b) ~ 0          has type `a`
  (a ~= b) ~ 1          has type `b`

The reason type is used here instead of evaluation,
is because `x : 0` means `x` is a way to construct `0`.
With other words, `x` is a proof of `0`.
