The Anchorite (1976)

In this tragicomedy, loosely based on a tale by Anatole France, Fernando Fernan Gomez plays a man who has locked himself away in the bathroom of his apartment in Madrid after furnishing it with various necessities. In a feeble attempt to communicate with the far-distant world, he flushes aspirin bottles filled with messages down the toilet, reasoning that they will reach the sea eventually. After almost a dozen years, one of his messages reaches someone who finds the idea of responding somewhat amusing. The mistress of a millionaire looks him up, and decides to seduce him...