Does someone say this is to not compare Wu Si to take? I of one face doubt examine next data rapidlyDoes everybody feel what this is east? The Christian era 1858, german mathematician not compares Wu Si (Mobius, 1790 ～ 1868) Li Siding of · of peace treaty writing discovers: Turn round a scrip after 180 ° , both ends is stuck again receive rise the punched tape circle of make it, have magic the property like. Common punched tape has two sides (namely bilateral curved surface) , a front, the opposite, two faces can besmear different color; And such punched tape has a side only (namely odd side curved surface) , only small bug can climb whole curved surface and need not have crossed its brim. This kind of punched tape is called " Mobiwusi is taken " (that is to say, its curved surface has only) .