Matthew Greenfield of StoneWork Capital answers the above question thusly:
“Using ten racks of co-located blade servers, one quant can detect a janitorial inefficiency, step in between janitor and light fixture, and screw in 49,500 bulbs in less than a millisecond, keeping five hundred lightbulbs of profit.
Two quants competing with each other can screw in 99,998 bulbs in a millisecond, with each quant retaining a profit of one lightbulb.
When ten quant firms try to screw in a light bulb, the bulb explodes, the light fixture gets ripped from the ceiling, the building falls down, the entire electrical grid of the city of Greenwich shuts down, innocent civilians all over the world have their retirement accounts electrocuted, and the Federal Reserve has to give the counterparties of each quant firm five hundred million light bulbs to maintain the stability of the system.
Afterward, each of the ten quant firms subjects its strategies to a probing and relentless critique, hires fifteen additional Ph.D.’s from MIT, Cal Tech, Harvard, and the Indian Institutes of Technology, buys four new supercomputers, and searches for new arbitrage techniques and algorithms.
Independently of each other, each of the ten firms develops the same brilliant and innovative strategy of “Knock knock, who’s there?” arbitrage.