What is a ABCD rhyme scheme?

In poetry, an ABCD rhyme scheme is a pattern of end rhymes in which the first and third lines rhyme with each other, and the second and fourth lines rhyme with each other. This rhyme scheme is often used in quatrains (four-line stanzas), but it can also be used in longer poems. Here is an example of an ABCD rhyme scheme:

> The cat sat on the mat, (A)

>And looked at the rat. (B)

>The rat ran away, (C)

>To play another day. (D)

In this example, the first and third lines ("mat" and "rat") rhyme with each other, and the second and fourth lines ("looked" and "play") rhyme with each other.