A fanciful post to Thingiverse from 3DTOPO allows you to print out your own version of Arthur Ganson sculpture Machine with Concrete , a system of wormgears that produces a gear-ratio of 244.14 quintillion to 1.
This is a printable version of Machine with Concrete. The sculpture is a series of twelve 1:50 worm gears, with each gear reducing 1/50th of the previous gear. With 12 gears, the final gear ratio is a mind boggling 244,140,625,000,000,000,000 : 1 (244.14 quintillion to 1). With the first gear spinning at 200RPM it would take over 2 TRILLION years for a single revolution at the end of the machine, so the final drive shaft can be embedded in concrete or plaster.
I emailed Arthur Ganson a link to this page and he replied "looks FANTASTIC!".