生物柴油

生 = 牛 + 一 : Mnemonic symbol: a cradle.

Sherlock Holmes (sh) comforts a crying baby bull (牛) in a cradle (生) in front of the engine ((e)ng1) and plays him a tune on a flute (一).

物 = 勿 + 牛 : Willy Walrus (w) wants to become a physicist (物) and does research about dark matter (物) in the space station's bathroom (Ø4). His motivation is to become a super villain and rule the world. Just as he is about to have a breakthrough, a huge black ox (牛) flying with the help of bat wings (勿) hits Willy with an oxerang and takes away the dark matter, saving the world.

柴 = 木 + 此 : Charlie Chaplin (ch) found new boots (此) under the Christmas tree (木) in the airplane's kitchen (ai2) and is eager to try them out. He gets some firewood (柴), makes a fire and is amazed that with the boots he is able to walk over the fire. He is so amazed that he spontaneously walks all over the Christmas tree (like indicated in the character 柴).

油 = 氵 + 由 : Maud Younger (y) is creating art in the outhouse's kitchen (ou2). She is painting a picture using oil (油) paint and occasionally using water color stored in a water bottle (氵). She is nipping a cuba libre (由) and from time to time even using her drink as color for her picture.