發送短信 : Video analysis of rolling cylinders

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