Many of the responses mention meditation, which I think is exactly what this is. With meditation we usually think of certain ways of managing our thoughts or breath or using some sort of mantra (I've never tried that last one), but I think any exercise that is challenging our ability to focus is functioning as mediation.

It also reminded me of "The Wonderful Story of Henry Sugar" which is one of four Roald Dahl stories that Wes Anderson made into short films for Netflix.