function weightAdjustment(factor) {
  return (onRefs, onOffsets, offOffsets) => {
    const adjustedOnOffsets = onOffsets.map(pt => [ pt[0] * factor, pt[1] * factor ]);
    return [ onRefs, adjustedOnOffsets, offOffsets ];
  }
}
Weight adjustment
@param  { number } factor Weight adjustment factor
@returns { Filter }