The old soda fountain
seven flavors for a nickel
scoops of ice cream like a mountain
two straws if you’re on a date
one each, if a kiss you count on!
take tiny little sips
from the stool, the kind you mount on
if you fall, you’re in a pickle!
when ‘tis over, love’s the outcome!



The Magic 9 poetic form is a great example of how a simple form can be created from a mistake and how some of the simplest forms are also the most fun to write.
the magic 9 is a newer form and relatively unknown. In fact, I couldn't find a creator of the form, though it appears to have been inspired by a poet misspelling the word "abracadabra."
This 9-line poem doesn't have any rules as far as meter or subject matter--just a rhyme scheme: abacadaba.