發送短信 : Random mechanism design on multidimensional domains

   _____   _    _    ______    _    _    ______   
  / ___// | || | || |      \\ | || | || |      \\ 
  \___ \\ | || | || |  --  // | || | || |  --  // 
  /    // | \\_/ || |  --  \\ | \\_/ || |  --  \\ 
 /____//   \____//  |______//  \____//  |______// 
`-----`     `---`   `------`    `---`   `------`