Verse written in tetrameter has four measures, which are also called feet. An example of four lines of tetrameter is the first stanza of the introduction to Milton,by William Blake:
"And did those feet in ancient time Walk upon England's mountains green? And was the holy Lamb of God On England's pleasant pastures seen?"
"However mean your life is, meet it and live it: do not shun it and call it
hard names. Cultivate poverty like a garden herb, like sage. Do not trouble
yourself much to get new things, whether clothes or friends. Things do not
change, we change. Sell your clothes and keep your thoughts."