This is the last time I explain how it's done (2020)

MDF, styrofoam, aluminum profile, perspex, floor isolation, plasterboard, fluorescent light
265cm * 295cm * 30cm

 
 
http://verkstad.nl/files/gimgs/th-92_1_v3.jpg
 
 
http://verkstad.nl/files/gimgs/th-92_2_v3.jpg
 
 
http://verkstad.nl/files/gimgs/th-92_3.jpg