How do you write a isomorph poem?

To write an isomorph, you repeat a single pattern of lines, adding one more word every line. Isomorphs are very short and only repeat their pattern a few times.

Here's an example of an isomorph:

>A bird sits

A small bird sits

A small brown bird sits

A small brown bird sits on

A small brown bird sits on a

A small brown bird sits on a limb