正弦波

正 = 一 + 止 : Mnemonic symbol: a stick-figure with straight lines. James II of England (zh) really has to use the engine's bathroom ((e)ng4), but there's a stick-figure (正) blocking the stalls with a barrier (止). The stick-figure measures with a flute (一) whether James is tall enough to go. James stands very straight (正) to make himself as tall as possible.

弦 = 弓 + 玄 : Marie Curie (xi) is getting trapped by black lava (玄) in the anthill's kitchen (an2) and all she has is a composite bow (弓). She plucks the string (弦) of her bow so that the chord (弦) resonates with the lava, causing it to stop its flow.

波 = 氵 + 皮 : Before entering observatory every visitor has to take off their shoes, so there are a lot of leather shoes (皮) in front of the observatory (o1). Beelzebub (b) cannot miss the opportunity to make a huge wave (波) by pouring his water bottle (氵) and to flush away all the shoes.

波 = 氵 + 皮 : Before entering observatory every visitor has to take off their shoes, so there are a lot of leather shoes (皮) in front of the observatory (o1). Beelzebub (b) cannot miss the opportunity to make a huge wave (波) by pouring his water bottle (氵) and to flush away all the shoes.