A simple recursively defined distribution on the integers.

```
(define (geometric p)
(if (flip p)
0
(+ 1 (geometric p))))
(hist (repeat 300 (lambda () (geometric .5))))
```

Alternatively, we can write the geometric distribution in tail-recursive form:

```
(define (geometric-tail p n)
(if (flip p)
n
(geometric-tail p (+ n 1))))
(hist (repeat 300 (lambda () (geometric-tail .5 0))))
```