One of the things that go lets you do is pass functions around.
I started the year talking about under from the j language. Which lets you 'bookend' some function with another function (a verb) and a function which undoes that function (obverse).
A great example is Pythagoras' theorem:
- You perform some 'pre-processing' on each value (squaring)
- You add all the values up
- You square root the result