重工业

重 = 千 + 里 : Mnemonic symbol (from the shape of the character): this one looks like a space elevator. The two top strokes are the heavens, the two bottom strokes are the earth, and the part in between is the cabin (or climber) of the space elevator.

Chantal Chicken (chu) is working in the engine's kitchen ((e)ng2). Her job is to crush sunflower (里) seeds with a 1 kg weight (千) to get the kernels. Then she has to put the kernels into the cabin of a space elevator (重) to send them to outer space. This repeats (重) again and again day in, day out.

重 = 千 + 里 : Mnemonic symbol (from the shape of the character): this one looks like a space elevator. The two top strokes are the heavens, the two bottom strokes are the earth, and the part in between is the cabin (or climber) of the space elevator.

Julian Giant Squid (zhu) installed a space elevator (重) in the engine's bathroom ((e)ng4). For the maiden trip, and as a stress test, he loads one thousand (千) one kilogram weights (千) and decorates them with sun flowers (里) to celebrate the occasion.

工 = 二 + 丨 : Mnemonic symbol: a steel beam, since 工 looks like the cross section of a steel beam.

Gitta Giraffe (gu) is working a shift in front of the engine ((e)ng1). Her job is to melt dinosaur bones (丨) so that they can be disposed off easily. To melt the bones, she is shorting a huge capacitor (二) with a steel beam (工) which consequently heats up to a bright glow. Using the glowing hot steel beam she can melt the dinosaur bone easily.

I can't help but see a bullfrog in 业. Maud Younger finds that the climate in the elevator's bathroom are perfect for her new business: growing bullfrogs.