Hey, I am writing you, because I did not watch the video, did not read the text, can't comment there, still I'd expect for your waterjet cutting text that you include that fine sand particles inside the water are used for the real cutting, since they are an essential part of the waterjet cutter.
a follower of your physics collection
74693288s ago, by Antonio
I added you to my circles...you can comment from now on.
74692875s ago, by CorinaMarinescu