The Potter's Wheel
A potter's wheel spun at a constant speed. She could shape one pot at a time.
A merchant offered her triple pay to make three times as many pots.
"Then I'll need three wheels. Or three potters."
"Just work faster."
"Faster clay flies off the wheel. You'll have no pots at all."
The merchant found another potter willing to try. He received a box of broken pieces.