I tend to work from only the vaguest ideas, not sketches. I work by making something I have an idea to do and then refining it.
This last firing I made a number of octagonal plates and then moved from there to legged plates, using the equilateral triangles I cut from the edges. I got bored with that and so I started out with a piece of square clay. I found a right angle triangle from my box of children’s blocks. After trimming all four sides of the clay slab, to my surprise, I was left with a square, just like when I started. I always have to laugh when meandering down a path takes me somewhere a more rational approach would have informed me of.