I made the layout lines as dark as I could so they would show-up clearly as I planed off the corners.  There are layout lines along the edge of the blades as well. 

I used a block plane to shave off the corners of the blade, and by the time I got to the eighth edge, I was getting pretty good at it.  I was pleasantly surprised to find out that the angular layout lines yielded a very fluid shape when finished.