Geometry

In example:

I'm writing a poem about a cat.
He likes to wear a silly hat.
He got it from the grocery store,
But he lost it and can't wear it anymore.

Or:

I have a dog
His name is Spot
He sleeps on a log
Outside when it's hot.

Every other line could rhyme, or 2 lines at a time could rhyme when going for poetry with rhyme scemes. The most popular rhyme schemes can be found in Sonnets.

. ABBB
is a type of poem with a ryme.

Rhyme scheme is the regular pattern of rhyming words in a poem or stanza. Letters are assigned to the last word of each line of a poem to help decipher a poem's rhyme scheme.

For example, the rhyme scheme of a Shakespearean sonnet is abab cdcd efef gg

All of the a's rhyme with a's, b's with b's, c's with c's, and so on.
A rhyming scheme is a stanza of a story often found in a poem. The end words of these stanza lines often rhyme with each other.