This may not be the easiest way...

...but it was the only way I could think of to build the form for the brick pathway. First, I used some of the FSC lumber purchased for the wall framing (yes, someday I hope to actually put up walls!) to make 20 ft long temporary 'joists'. These were rested on the perimeter of the foundation form, spaced apart about 18" or so. I then attached strips of scrap plywood vertically down from the joists and resting on the foundation bed, following the desired outline of the pathway. Next I ripped more of that Masonite siding (the same stuff used to build the silo form) into 3" strips and attached them to the verticals to make the rounded edge for the pathway. The Masonite wants to break when bent into a tight radius, so I had to make hundreds of shallow kerf cuts in it wherever a sharp corner was made. This took some experimentation, but it worked out okay. Once it was shaped just right, I installed 'spreaders' across the inside to hold everything together (I was able to use old barn board scraps for this), then removed those joists to reveal the pathway form. Voila- all this took another couple of days to fabricate. The lengths I will go to just to salvage the old barn bricks!