I'm just applying his idea as I think it is a great way to view the strength of currencies relative to one another. Especially for a trader like me who is a trend trader. Here we can see the Pound (red line) in an overall strong trend, while the Yen (blue line) has been in a trend for sometime.
I have been short GBP/JPY since February 4th, with multiple positions running.
Hope this helps someone see the power and profitability of trading trends.
(Side note, I have been working with the calculations of the values, but even if it currently may not be perfect it still gives a good picture of the strength of a currency)