樹皮

树 = 对 + 木 : Sheldon Shrimp cultivates a Christmas tree in the space station's bathroom. He is very happy that he found the right tree, just the one he imagined, and—in his mind—marks of the tree he imagined with a big green check mark.

皮 = ㇖ + 丿 + 丨 + 又 : Mnemonic symbol: a cow's hide.

皮 = ㇖ + 丿 + 丨 + 又 : Just inside the entrance of the space station Pocahontas destroys her cow's hide with a sickle because she decided to go vegan. Instead of leather she'll wear a banana peel as coat, boxing gloves as shoes and a big dinosaur bone as long hat.

皮 = ㇖ + 丿 + 丨 + 又 : New mnemonic symbol, since I also use the cow's hide for 革: leather shoes.