Invisible drawings?

Reading about Walter De Maria and about the invisible drawings he did in the late 60s, I hope to see one, but no luck so far... they don't seem to show up at all on the internet ...

However in looking around I came across the work of Marco Maggi, who does some amazing drawings, on perspex cubes for example, and notably this one in pencil on a sheet of graphite
"Looks like quilting," said my son.

In an interview Maggi says: "I did an MFA majoring in Printmaking at the State University of New York. My interest was not in the print process. I focused on plates and particularly in the threshold between two and three dimensions, using engraving and embossing. As I write today, I am engraving a plexi-glass sheet but I will not print from it. I stop here. The framed plexi-plate projects a shadow on the paper. The technique could be called printing with shadow. You see the projection but you cannot see the real drawing on the plexi-glass. A spacer between the plexi sheet and the back paper is a second referent to three dimensions. In fact, the relationship between two and three dimensions is another very important dichotomy." That interview contains a link to his first video, using an apple - one photo every 10 minutes over 40 days - the video is 4 minutes long.

"He compiles a thesaurus of the infintismal and undecipherable" says the blurb for one of his exhibitions.

Here you can listen to an interview where he discusses how he became an artist, the idea of slow time, the relationship between Maggi’s work and the experience of reading a text, and other ideas.