發送短信 : Symmetry Groups of Two-Way Twofold and Three-Way Threefold Fabrics

 _____       ___    __    __     ___      _  _   
|  __ \\    / _ \\  \ \\ / //   / _ \\   | \| || 
| |  \ ||  / //\ \\  \ \/ //   / //\ \\  |  ' || 
| |__/ || |  ___  ||  \  //   |  ___  || | .  || 
|_____//  |_||  |_||   \//    |_||  |_|| |_|\_|| 
 -----`   `-`   `-`     `     `-`   `-`  `-` -`