Prop ] * 2;

			}
			set value( v ) {

				this.obj[ this.maxProp ] = v / 2;
				this.obj[ this.minProp ] = v / - 2;

			}

		}

		class MinMaxGUIHelper {

			constructor( obj, minProp, maxProp, minDif ) {

				this.obj = obj;
				this.minProp = minProp;
				this.maxProp = maxProp;
				this.minDif = minDif;

			}
			get min() {

				return this.obj[ this.minProp ];

			}
			set min( v ) {

				this.obj[ this.minProp ] = v;
				this.obj[ this.maxProp ] = Math.max( this.obj[ this.maxProp ], v + this.minDif );