![Image source: Universe pictures The Boundary Problem Image source: Universe pictures](http://www.timeone.ca/wp-content/uploads/2013/06/057-the-boundary-problem.jpg)
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Universe pictures
I want to show him how a simple edge can change our thinking. Let’s think, I say, about the way the world is viewed some six or seven hundred years ago. People think the world is flat. If you sail too far you will fall off.