Grumpy Old Geeks People William Playfair Person William Playfair 2 mentions in 1 episode William Playfair is described as a Scottish figure who invented the pie chart, bar graph, and line graph. Mentions 204: We're Lit! Apr 10, 2017 1:32:49 Have you heard of a guy named William Playfair? 1:33:21 he also invented the pie chart, the bar graph, and the line graph