Basic usage pattern of a curry function.


```js
const a = [1,2,3,4];
console.log(a.map(x => x*2));  // [2, 4, 6, 8]
```

Here is the same thing using currying.

```js
// Curry function
const mulby = y => x => x*y;

// New lambda partion
const mul2 = mulby(2);

console.log(a.map(mul2));      // [2, 4, 6, 8]
```