How to Scribe a board to match a slope

There are a lot of different ways to scribe a board to a slope, but in the context of building a garden bed, I found this to be the easiest method. This method for scribing works because my garden bed is built with 2x8's and I'm using another 2x8 as the guide for me to make my mark. If they weren't the same, this wouldn't work.

Also, with making the cut, a bandsaw or jigsaw would be better, but I don't own either tool. So I am making do with what I have. When the saw would start to bind I would stop making the cut and use a wedge to take some of the tension off the blade.