十二碼

十 = 一 + 丨 : Mnemonic symbol: a holy cross. Sherlock Holmes (sh-) is investigating a very strange thing he found in the kitchen of the space station (-2): A big pyramid made of ten (十) crosses (十), which are in turn made out of flutes (一) and dinosaur bones (丨).

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).

码 = 石 + 马 : Just when Mahatma Gandhi (m) and the unicorn (马) entered the ashram (a3) a giant rock (石) fell down and trapped them inside. There is an inscription written on it: if they ever want to leave, they will have to find the secret number (码) and say it out loud. There is also a hint: "how many roads must a man walk down?"