Wikipedia and All the King's Men both name the (0,3)-leaper the "Threeleaper" and the (3,3)-leaper the "Tripper", but neither lists an inventor or a variant that uses them.
Betza's notation uses H for a (0,3) leap and G for a (3,3) leap, but I don't recall ever reading how he chose those letters.
Wikipedia and All the King's Men both name the (0,3)-leaper the "Threeleaper" and the (3,3)-leaper the "Tripper", but neither lists an inventor or a variant that uses them.
Betza's notation uses H for a (0,3) leap and G for a (3,3) leap, but I don't recall ever reading how he chose those letters.