实属不易

实 = 头 + 宀 : Sherlock Holmes welcomes professor Skull just inside the entrance of the space station. Professor Skull has not a complete head but only a skull, and a solid understanding of solid state physics. She really is an honest person and still wears her graduation cap.

属 = 尸 + 禹 : 暴龙属 is the genus Tyrannosaurus, and I'll use a T-Rex as mnemonic symbol.

The great Yu (禹) built a dyke to prevent Sheldon Shrimp (shu) from entering his side of the space station (Ø3), but then a T-Rex (属) ghost (尸) starts to haunt him until he tears down his dyke.

不 = 丆 + 卜 : Bruno Bear (bu) is setting up a wind wheel (丆) with a voodoo staff (卜) in the space station's bathroom (Ø4). He also puts a "forbidden" sign (mnemonic symbol for 不) on it, to make clear that it may not (不) be stopped.

易 = 勿 + 日 : Mnemonic symbol: a really easy puzzle consisting of only two parts.

易 = 勿 + 日 : Maud Younger and the sun are trying to complete a really easy puzzle in the space station's bathroom. It's not as easy as they thought though, because in zero gravity they can only move with the help of their bat wings.

易 = 勿 + 日 : Mnemonic symbol: a really easy puzzle consisting of only two parts.

易 = 勿 + 日 : Maud Younger and the sun are trying to complete a really easy puzzle in the space station's bathroom. It's not as easy as they thought though, because in zero gravity they can only move with the help of their bat wings.