row_2 = row_1 + v_margin + 12; //knob_radius top_row = height - v_margin; working_increment = working_height / 6; // generally-useful spacing amount for vertical columns of stuff col_middle = col_left + (15.6 + 1.5 + 7 + 8); // pot + led + switch? Col_right = width_mm - h_margin; // special: the right-hand side tries to squeeze 6 rows into the space of 5 out_working_increment = working_increment * 4 / 5; out_row_2 = working_increment*1 + out_row_1; out_row_6 = out_working_increment*5 + out_row_1; out_row_9 = working_increment*8 + out_row_1; rotary_knob_row = top_row - 30; working_width = width_mm - h_margin; input_column = h_margin; col_right = width_mm - col_right + tolerance*4 + 8; //three knobs plus space between two resistors in the Source.