I would argue for ... mathematics.
ASIDE: Inspired by EWD1193[0] (and with a nod to XKCD[1]) it appears that despite there famously being no royal road to geometry[2], there is a road suitable --with a bit of plugging and chugging-- for the Little Engine that Could[3]. (End of Aside)
-Dave [0] "On arcs and angles", Dijkstra, 1994 http://www.cs.utexas.edu/~EWD/ewd11xx/EWD1193.PDF [1] "Game AIs", Munroe, 2012 http://www.xkcd.com/1002/ [2] "Commentary on the Elements", Proclus, ca. Vème [3] "Machine Proofs in Geometry", Chou, Gao, Zhang, 1994 http://www.mmrc.iss.ac.cn/~xgao/paper/book-area.pdf
