This is a lecture about the power of simple ideas in mathematics.
What I like doing is taking something that other people thought was complicated and difficult to understand, and finding a simple idea, so that any fool -- and, in this case, you -- can understand the complicated thing.
In this lecture, I'd like to take you through some simple ideas relating to squares, to triangles, and to knots.
Transcribed, edited, and illustrated by David MacKay, with help from Kele Baker and Sanjoy Mahajan, for inclusion in the book Power, edited by Alan Blackwell and David MacKay, CUP (2004).
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