Contact us
Choose a category below so we can get back to you as quickly as possible.
每一張紙均有兩個面和封閉曲線狀的棱(edge),如果有一張紙它有一條棱而且只有一個面,使得一隻螞蟻能够不越過棱就可從紙上的任何一點到達其他任何一點,這有可能嗎?事實上是可能的只要把一條紙帶半扭轉,再把兩頭貼上就…
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.