The triversen ("triple verse sentence") is a verse form invented by William Carlos Williams. Each stanza is composed of a single sentence, broken into three parts, which together form a stanza. The poems are generally unrhymed and often contain alliteration. They can be composed of any number of tercets.
You can learn more about the triversen and read some examples at Poetics and Ruminations.
So, there's your challenge for the week. I hope you'll join me in writing a triversen. Please share a link to your poem or the poem itself in the comments.