When the correct scale is used to study the market patterns
the Gann box works perfectly. Gann had his very specific plastic overlays
which he used on his charts, revealing the inherent geometry
between Time and Price.
I have extended a Gann Box on the Hang Seng
and you can see how the 45 degree line from the low in Oct 2011
has created both support and the recent resistance on the 3rd Dec 2013.