#polymethyl_methacrylate  a transparent plastic used as a substitute for glass
  supertype:  #acrylic_resin__acrylicresin__acrylic__acrylate_resin  a glassy thermoplastic; can be cast and molded or used in coatings and adhesives
  subtype:  #Lucite__Perspex  (trademark) a transparent thermoplastic acrylic resin
  subtype:  #Plexiglas__plexiglass  (trademark) a light transparent weather resistant thermoplastic

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