Yesterday was Civil Engineering Day in Japan. Why? Because the Japanese for "civil engineering" is "土木" (literally, "earth and wood"), from which you can handily extract "十一, 十八" (11, 18) if you're rough enough.

The word "土木" is popularly held to come from a passage in the 13th chapter of the Huainanzi, in which humanity's long history of being snowed on in the winter and bitten by horseflies in the summer finally ends when a certain luminary or luminaries has the good sense to 築土構木 ("pile up earth and arrange wood") into shelter.

(Osaka University, always the contrarians, apparently used to have a "構築工学科", literally "Arranging and Piling Engineering Department", but sheepishly switched to "土木" in the 60s.)