A problem or riddle written in rhyme for an artistic twist.
A rhyme is a repetition of the same sounds at the ends of two or more words, most often in the final syllables of lines in poems and songs.
Rhyme partly seems to be enjoyed simply as a repeating pattern that is pleasant to hear. It also serves as a powerful mnemonic device, facilitating memorization. The regular use of tail rhyme helps to mark off the ends of lines, thus clarifying the metrical structure for the listener. As with other poetic techniques, poets use it to suit their own purposes; for example in this riddle rhyming is used as a hint towards the solution.