In H. G. Muller's system, a range 2 slider just has an empty bulge. for sliders with range 3 or more, this is typically denoted by a plus sign or a shortened radial line, with the plus getting closer to the center the longer the range gets if that option is used. If you wanted a better system, you could have line perpendicular to the bulge for every square after the second square in that direction.
In H. G. Muller's system, a range 2 slider just has an empty bulge. for sliders with range 3 or more, this is typically denoted by a plus sign or a shortened radial line, with the plus getting closer to the center the longer the range gets if that option is used. If you wanted a better system, you could have line perpendicular to the bulge for every square after the second square in that direction.