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

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.google.co.uk/#q=digital+sundial http://www.digitalsundial.com/ http://www.digitalsundial.com/ http://en.wikipedia.org/wiki/Digital_sundial http://en.wikipedia.org/wiki/Digital_sundial http://www.freepatentsonline.com/5596553.html http://www.freepatentsonline.com/5596553.html http://community.middlebury.edu/~schar/sundial/patent.html http://community.middlebury.edu/~schar/sundial/patent.html ... and cast as a short story ... http://www.cthisspace.com/ftl/macaw/MR40.html http://www.cthisspace.com/ftl/macaw/MR40.html