二次曲線

二 = 一 : Mnemonic symbol: a capacitor, because the two strokes remind me of the symbol in electrical drawings. Albert Einstein (Ø) is experimenting with a capacitor (二) in the space station's bathroom (Ø4). He finds that it's uncomfortable to discharge a capacitor using two flutes (一).

次 = 冫 + 欠 : Mnemonic symbol: the cube, as in words involving 三次 relate to "cubic equations" or "cube (third power)". The King of Chu (c) pulls a popsicle (冫) out of the cube (次) in the space station's bathroom (Ø4) and leaves an IOU note (欠) on the cube.

曲 = 囗 + 卄 : Mnemonic symbol: a harp. Cupid (qu) is playing a harp (曲) in the space station's living room (Ø3). He's sitting on a big enclosure (囗), playing the harp (曲) and wielding a double axe (卄) at the same time.

线 = 戋 + 纟 : Mnemonic symbol: barbed wire.

线 = 戋 + 纟 : The silk worm wants to use the floating tank in the anthill's bathroom, but there's already Marie Curie inside—and she secured the tank by setting up barbed wire all around it.