Yes, so first will be to make a vertical plane of one of the edges, then hew the side opposite parallel to that one before rotating the blank 90 degrees onto one of the planes and squaring off what will be the underside of the gutter. This blank that the gutter will come from is actually a quarter section with the pith split out. In removing the pith section, it separated nicely along a single growth ring leaving a naturally concave surface and that is what I want to maintain if possible, for the gutter. This may or may not actually work and in the case that is doesn't I use first a gutter adz then smooth out the bottom with a plane. Sometimes there will also be a profile planed on the outer lower edge though not this time.