Situation: I am writing on the board with the desk to my right within reach.
Alternative situations: Standing with the desk on my right, I am about to move the board from the wall in front of me to the bookshelf in my 10 o'clock direction. I am facing the board and writing notes down with a marker, the chair is to my left side.
Question: What shape on the floor does the light coming through the door behind me form?