知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。N.R. in SeoulN.R. in Seoul 64511 gold badge88 silver badges1515 bronze badges 3 Only for clarification on the authentic gum - On this planet of philately (Stamp amassing), unique gum signifies that the stamp was never connected to nearly anything, b