"The Mad Gardener's Song" is a poem by Lewis Carroll that appears in his book Sylvie and Bruno (1889, 1893).

He thought he saw a Garden-Door That opened with a key: He looked again, and found it was A double Rule of Three: "And all its mystery," he said, "Is clear as day to me!"

He thought he saw an Argument That proved he was the Pope He looked again, and found it was A Bar of Mottled Soap.

"[5] "The Mad Gardener's Song" featured on the BBC show Play School in 1981.

[6] Composer Stuart Findlay set "The Mad Gardener's Song" to viola, clarinet and piano in 1994.