Cannot find better introduction about Bret Victor than this:
Came to know about Bret Victor when I was looking what Mike Matas http://www.mikematas.com was doing at Push Pop Press. I was thinking Bret Victor was working in FB, but feels good that he is not.
Have been seeing and reading his output for around 10 years. Everything is fascinating and always gives a new perspective about computer science field. Bret created more interest in Alan Kay's work and came to know about a great person Douglas Engelbart
His paper Magic Ink (http://worrydream.com/MagicInk/) is a must read for every computer science engineer.
Need to check regularly https://github.com/cdglabs whats brewing.