Such compasses triangle I had the technical study in use. So get me always fast and good sketches. The set square is in 2mm spacing offset holes for stable Stift.- Kuli goes / ink probably not. - By pressing the red circle flips a needle into the paper and you can draw circles about this center, by turning the triangle with the stylus. This you have to practice a little, so that one does not slip and can draw around the second hand. It works then but good. Who stands in a restricted space on paper / sketch, it can be safely used well. The circle triangle is made of flexible material and has all the characteristics of a protractor. Even a (very) small handle is available. As an extra, there is a scale from 0 to 2 pi on one side.
