工
=
二
+
丨
:
Mnemonic symbol: a steel beam, since 工 looks like the cross section of a steel beam. In front of the engine ((e)ng1), Gitta Giraffe (gu) is doing some hard work: She's stacking a capacitor (二) on a dinosaur bone (丨) on a capacitor (二). She's not very successful, but then she gets the idea to use steel beams (工) as support.
艺
=
乙
+
艹
:
Maud Younger (y) got a silver medal (乙) for her mad gymnastics skills (艺) In the space station's bathroom (Ø4), where she performed her gymnastics on sheets of artificial lawn (艹).