(1) In 1966 he abandoned painting for sculpture in perspex and neon, then turned to photography, film, and Conceptual art.(2) The perspex cover was also screwed in place with polished stainless screws.(3) I suggest you get small pieces of glass or perspex and use these as the final filter.(4) The clear perspex side panels and bigger wind deflectors are optional.(5) It's quite weird because they're squashed between bits of transparent perspex , so you can see them in their flattened state.