What is an example of a seven line verse?

A seven line verse is called a Rondelet.

A rondolet contains two rhymes with a seven line stanza. The lines have 8 syllables each, the refrain has 4 syllables with a pattern of 4/8/4/8/8/8/4

Example

Eating red gum

is so very very nice sometimes

Eating red gum

feel like strawberries in the sun

or better yet a candied lime

that broke out of jail commits a crime

Eating red gum