Row, row, row your boat ...
Every American child knows this song by heart. Technically, it's called a "round", where different groups start singing the same things at different times. It's simple enough to get large groups of children to do it at school concerts - and well done! Having been to my share of school concerts (as both performer and listener), this is A Very Good Thing Indeed for teaching our children the basics of music. It's a very old music form, dating from the High Middle Ages. Keep the Dream alive, everyone!
But what happens if you complicate things just a bit? Say, by adding an extra (and new) melodic theme to the plain, old, boring Round? You get this:
It's called a "Canon", and Johan Christoph Pachelbel created what is undoubtedly the most famous version, composed in the 17th Century. Surprisingly, it was lost, and only re-discovered after World War I. I say "surprisingly" because this piece is hugely popular today. You've probably heard it.
But "Canon" is not the same as "Cannon", which involve not a chamber quartet, but black powder, but may involve a repeated theme (shelling the enemy). It took until the 19th Century and Tchaikovsky to write a piece for orchestra and Field Artillery, but this is a doozy. It's another piece that you've almost certainly heard before, the 1812 Overture, written to celebrate the defeat by the Russian Empire of Napoleon's Grand Armeé in 1812. Literally, it was scored for orchestra and field artillery. In other words, cannons.
And now for a personal anecdote. When I was pursuing the lovely and сложный Mrs. Borepatch, we went on a date to the National Mall (we lived in the Washington D.C. suburbs at the time) to see a concert by the National Symphony playing the 1812 Overture. Accompanied by 105 mm Howitzers (cannons) from the 517th Field Artillery Battery* . They'd light one off, and everyone would cheer. They'd light the next off, and everyone would cheer. Good times, good times.
And so, a single character makes a difference, but you'll get great music whichever way you like to spell canon/cannon. I kind of think that my High School music teachers would be appalled reading this, but it's true.
Oh, and for a very politically incorrect and a totally awesome version of Earth Shattering Kaboom done to the 1812 Overture, here's nuclear detonations to replace the puny 105 mm cannons.
* OK, it's a fair cop. I can't remember the unit number. In the unlikely circumstance that one of the artillerists runs across this post, that you for your service, and thank you for a fabulous evening of entertainment.