The world's simplest machine for popping a balloon? A pin.
The most complex? Well, that's a bit harder to explain.
The Purdue Society of Professional Engineers has smashed its own world record for most-complex 'Rube Goldberg' contraption ever devised.
Named after a popular cartoonist known for designing humorously complex inventions, the idea of a Rube Goldberg machine is to achieve a task in the most convoluted way possible.
Competitions are held across the world to see who can design the most interesting, inventive and silly variations on the theme.
None can match the Purdue team, however, who at the US National Rube Goldberg Machine Contest took the People's Choice Award with a machine comprising 300 separate steps.
The team from the Society of Professional Engineers and the Society of Hispanic Professional Engineers took more than 5,000 hours to construct the machine which, when functioning, accomplished every task ever assigned in the competition's 25-year history including: peeling an apple, juicing an orange, toasting bread, making a hamburger, changing a light bulb, loading a CD and sharpening a pencil.
It also included an old steam whistle and a large, protruding hand which popped the balloon.
Take a look at the machine below, with a few of our other favourite Rube Goldberg devices.