P. Boughton (2003) - Real Gann Angles.(pdf)

The diagonal of a square with a base of 1 is 1.414, or square root of 2, or a 45 degree angle. The S&P 500 high in 1994 482, time 1.414 = 681 which was the next high in the SP in the middle of 1996. So we can say 681 is 45 degrees from 4 price angle. And, 681 x 1.414 = 964 is another 45 degree price angle. (Editor's note: 482 x 1.414 x 1.414 = 482 x 2 = which is the same as 482 at a 60 degree angle.)