發送短信 : Topological interface state formation in an hourglass lattice sandwich meta-structure

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