thumb|300px|An example of a crab canon.Riemann, Hugo (1904). Text-book of simple and double counterpoint including imitation or canon, p.185. Breitkopf & Härtel.
thumb|300px|An example of a crab canon.Riemann, Hugo (1904). Text-book of simple and double counterpoint including imitation or canon, p185 Breitkopf & Härtel.