I was wondering if the author came up with that graph himself so I looked around a bit. The graph was coined originally by a hungarian psychologist, Mihaly Csi

I was wondering if the author came up with that graph himself so I looked around a bit. The graph was coined originally by a hungarian psychologist, Mihaly Csikszentmihalyi [1] and published in 1997 and has not been undisputed. Personally, I found the wikipedia article on flow [2] quite interesting. [1] https://en.wikipedia.org/wiki/Mihaly_Csikszentmihalyi https://en.wikipedia.org/wiki/Mihaly_Csikszentmihalyi [2] https://en.wikipedia.org/wiki/Flow_%28psychology%29 https://en.wikipedia.org/wiki/Flow_%28psychology%29