From The Art of Tying the Cravat: Demonstrated in Sixteen Lessons (1828), the Cravate en Cascade is meant to look like a cascading waterfall.
For more on cravats:
Regency Fashion: Putting on a Cravat – Regency Reader (regrom.com)
Regency Fashion: The Cravat a l’Americaine – Regency Reader (regrom.com)
Regency Fashion: Cravate a la Byron – Regency Reader (regrom.com)
Regency Fashion: Cravate Sentimentale – Regency Reader (regrom.com)