Describir: 'Gläserne stoffe' Changierende stoffe

  _  _     _____               _____                ___      _____      ___    
 | \| ||  |  ___||     ___    |  ___||   ____      / _ \\   / ____||   / _ \\  
 |  ' ||  | ||__      /   ||  | ||__    |    \\   / //\ \\ / //---`'  / //\ \\ 
 | .  ||  | ||__     | [] ||  | ||__    | [] ||  |  ___  ||\ \\___   |  ___  ||
 |_|\_||  |_____||    \__ ||  |_____||  |  __//  |_||  |_|| \_____|| |_||  |_||
 `-` -`   `-----`      -|_||  `-----`   |_|`-`   `-`   `-`   `----`  `-`   `-` 
                        `-`             `-`