In my schooling, I turned to mathematics and science, bored with traditional classic education.
During WWII, I was called out of college to man an antiaircraft gun site...but I spent my time creating new improvements to gunnary calculations using radar and the wireless.
I was a master of the mechanical desk calculator and the early computers (i.e. held 1961 world record for keeping a computer working without a breakdown for 39 hours).
I helped create the area of Monte Carlo simulation, and am considered the father of mathematical percolation techniques.
I am considered one of the "outstanding problemsolvers of 20th century mathematics."
Answer:
John Hammersley (1920  2004)
