Tanka is a form of poetry similar to haiku. It's short, and the lines don't need to rhyme. The just must have a set number of syllables: 5/7/5/7/7.
Today's tanka prompt is: trees.
a walk through the woods.
shady canopy above
our heads. the breeze makes
whispering sounds. the fresh smell.
ground spongy under our feet.