I'm in London, outside the main parliament or palace, at the crossing of the river Thames and another river. The two rivers cross like an X, and on windy stormy days like this one, this creates a complex interference pattern of waves. One great big one builds, towering plenty high enough to overcome the guard rail and wash up onto the park in which I stand, but it is narrow and pointed, so I have only to step aside a few feet and watch it crash.

Somebody is with me, but meandering along the park, and they ask me if I'm not scared of these waves. I say no, they are predictable, they will only happen in certain ways.

Nearby there is a gift shop, where I buy a baking pan that represents this pattern, and it is also apparent to me that a similar pattern exists in the financial markets.