Philosophy of Mathspeaking topic

You cannot paint the inside surface of an infinitely long horn, because that would take infinite paint; yet you can fill the same horn completely with liquid paint, because its volume is finite. How can one surface be both unpaintable and fillable?

Gabriel's Horn (Torricelli's trumpet)

practice with this topic

Set the timer (5-30 min), take 20 seconds of prep if you like, start talking. Jot your thoughts onto the sticky-note board.