A **chain** of three discrete nodes:

```
(define a (flip))
(define b (flip (if a .3 .5)))
(define c (flip (if b .2 .4)))
c
```

A **chain** of three continuous nodes:

```
(define a (uniform 0 1))
(define b (uniform 0 a))
(define c (uniform 0 b))
c
```

A **tree** with five nodes, two forks:

```
(define a (flip))
(define b1 (flip (if a .3 .5)))
(define b2 (flip (if a .2 .4)))
(define c1 (flip (if b2 .1 .2)))
(define c2 (flip (if b2 .5 .6)))
c2
```

An **inverse tree** with five nodes, two joins.

```
(define a1 (flip))
(define a2 (flip))
(define b1 (flip (if (or a1 a2) .3 .5)))
(define b2 (flip))
(define c (flip (if (or b1 b2) .4 .6)))
c
```

A **diamond** shape with four nodes:

```
(define a (flip))
(define b1 (flip (if a .3 .4)))
(define b2 (flip (if a .4 .5)))
(define c (flip (if (or b1 b2) .2 .3)))
c
```