```
sbcl --script day-00/part.lisp
```

lambda christmas tree

```
       λ
   λf.λz. z
  λf.λz. f z
 λf.λz. f f z
λf.λz. f f f z
       x
```

```rust

true
| T = (λx.λy.x) 1 2 -> 1

false
| F = (λx.λy.y) 1 2 -> 2

if = (λb.λt.λf.btf)

not = (λa.if a F T)
| (λb.λt.λf.btf) a F T
| ()

and = (λab.if a b F)


```

```rust

(λb.λt.λf.btf) true 1 2 -> 1
= (λx.λy.x) 1 2 -> 1
= (λx.x) 1 -> 1
= x 1 -> 1

```