The quatrain of seven steps is like a little game that poets play. It's a special way of writing a poem with four sentences, called a quatrain, but each sentence has to have exactly seven syllables.
It's like taking four steps, but each step has to be exactly the same size. You have to count very carefully to make sure each step is the right size.
When poets write a quatrain of seven steps, they have to be very careful to choose their words and make sure each sentence has the right number of syllables.
It's kind of like a puzzle that only works if you get all the pieces just right!