Logogriff ( Greek λόγος - word; Greek γρῖφος - network) is a poetic and stylistic device, which consists in constructing a phrase so that the number of letters or sounds in the original word or phrase gradually decreases (usually at the beginning of the corresponding word). An example of a logogriffic verse in Russian poetry is the epigram of L. N. Trefolev to the Chief Prosecutor of the Synod K. P. Pobedonostsev :
Pobedonostsev for the synod,
Edible bearers for the yard,
Poor bearers for the people
And scammers for the king.
Also, a poetic riddle based on a similar principle can be called a logogriff.