Like Sherlock Holmes’s a “three-pipe problem” in "The Red-Headed League" (1891), requiring an interval of quiet, creative thought. I first came across the phrase in the thread φέρνω / ρίχνω / πιάνω (κάποιον) στο φιλότιμο by Nickel, #4 by Sarant:
Πολύ ενδιαφέρον, αν και η τελευταία παράγραφος ή...