row_2 = row_1 + v_margin + 12; //knob_radius top_row = height * rotate_vector_cos; [left_edge, rotate_vector_cos * rail_depth], // top horizontal rib // one more to mount a circuit outside the full dev board (in some cases) Arduino + DAC https://www.youtube.com/watch?v=t3kUPjdiq0o for.