It could be very useful to have a facility for drawing straight lines which are at a specified angle to another such straight line. Maybe that is asking a lot, but I can't see why it shouldn't be possible. Ideally I'd like to see arbitrary angles, such as 27.25 degrees, but I believe at the present there are only accurate horizontal and vertical line possibilities. The lines could be part of a drawing or diagram or photo, or simply grid lines for positioning other objects, to be removed later.