Bach Crab Canon Visualized
By Ralph Graves
Music may be an audible art form, but sometimes visuals can help, too. Jos Leys, who normally works in the field of mathematics, has created a short film illustrating Bach’s “Crab Canon” from the “Musical Offering” in action.
Now, I could tell you that what makes this composition such a tour de force is its simple complexity. A crab canon, or cancrizan, is sort of like a round. A melody starts off, and then the second voice comes in a few beats later, and this single tune layered against itself creates the harmony (like “Row, Row, Row Your Boat”).
But a crab canon has the second voice enter with the melody in reverse. So the art is to construct a tune that makes sense forwards and backward — and can harmonize with itself in the process. Hard to understand? I agree. That’s why I like this video. View, and enjoy.
