

Objects casting different shadows in different planes - RiderOfGiraffes
http://www.fastcodesign.com/1662094/an-impossible-object-that-would-make-mc-escher-drool

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RiderOfGiraffes
This is a pretty simple version of a theorem in math that says that any
countable collection of shadows can be cast (up to an error of area measure
zero) from a single object.

In other words, you can make an object that casts a shadow that is the time of
day - digital or analog.

I'm pretty sure you can buy these things - let me go look ...

OK:

<http://www.google.co.uk/#q=digital+sundial>

<http://www.digitalsundial.com/>

<http://en.wikipedia.org/wiki/Digital_sundial>

<http://www.freepatentsonline.com/5596553.html>

<http://community.middlebury.edu/~schar/sundial/patent.html>

... and cast as a short story ...

<http://www.cthisspace.com/ftl/macaw/MR40.html>

