工 craft or industry

as in : "The crafty drug mule smuggled COCAINE on the plane in his COLON. "

It looks like a cross-section of an iron girder. Since this is the kanji for factory (工場), you can think of it like, a girder made at the iron factory.

construction ★★★★★
工 (craft or industry) + 事 (action/ incident) = 工事 (construction)

construction work - buildings or roads, i.e. what guys do outside your window.

factory ★★★☆☆
工 (craft or industry) + 場 (place) = 工場 (factory)

man-made ★★★☆☆ NEO
人 (person) + 工 (craft or industry) + 的 (motivation / '-al') = 人工的 (man-made)

carpenter ☆☆☆☆☆ FP
大 (big) + 工 (craft or industry) = 大工 (carpenter)

carpenter. How awesome is that!???! Seriously, I wouldn't even believe my friend when he told me,I was like, 'Cmon, grow up.' He was like, "What is so funny about a daiku carpenter?" I made him look it up in the dictionary and prove it.