- Thu Dec 29, 2016 9:16 pm
#197100
Found in the exercises of my real analysis book, Abbott's Understanding Analysis. Fantastic book, would highly recommend.
Imagine a clock where the hour hand and the minute hand are indistinguishable from each other. Assuming the hands move continuously around the face of the clock, and assuming their positions can be measured with perfect accuracy, is it always possible to determine the time? (And no, watching which one goes faster doesn't count—imagine we only get their positions at a specific moment.)
The solution:
~dlgn
Imagine a clock where the hour hand and the minute hand are indistinguishable from each other. Assuming the hands move continuously around the face of the clock, and assuming their positions can be measured with perfect accuracy, is it always possible to determine the time? (And no, watching which one goes faster doesn't count—imagine we only get their positions at a specific moment.)
The solution:
Spoiler:
I am the whirring thing past the corner. I am the darker patch under the bed. I am the tapping on your window; the extra steps on the sidewalk; the voice whispering your name. I am Stalkerbot, and I am watching you.