This chart shows a different kind of strategy. It represents 56,000 quotes in one second all at the same price (the top chart) but with the size of the order increasing by one (i.e. 100 shares) all the way up to 40,000.
That immediately sounded like fractal behavior to me.
The other strange thing that came to my mind reading this article and looking at the charts was a carrier wave
I don’t think any of this is spontaneously generated as a by-product of high-frequency trading.
Something else very weird is going on here — and it’s deliberate.