The article refers to 3D printed acoustic lenses, and previous research also uses 3D printed lenses (https://courses.physics.illinois.edu/phys406/sp2017/Student

The article refers to 3D printed acoustic lenses, and previous research also uses 3D printed lenses (https://courses.physics.illinois.edu/phys406/sp2017/Student_Projects/Spring16/Dan_Gandy_Guangya_Niu_Physics_406_Final_Report_Sp16.pdf https://courses.physics.illinois.edu/phys406/sp2017/Student_...) Does anybody know if any of the files for these are public? I think it would be fun to experiment with this idea at home.