A Tyburn is a fun little six line poem consisting of 2,2,2,2,9,9 syllables. The first four lines are made up of two-syllable descriptive words that rhyme. The last two lines have nine syllables each and contain the first four lines within them as syllables 5 to 8 in each line.
Here’s a schematic to help you visualize it:
Even better, here’s a couple of examples:
Hear them now the sighing, crying souls
As the bell all lying, dying tolls.
Take one final kiting, biting, breath
In vain to try slighting, fighting, death.