of the drawings with continuing reference to fig1 it can be shown that the present invention 10 may further comprise a first center member 20 having respectively opposed first and second ends thereof with the first end of the first center member being pivotally connected to the second end of the first outer member 12 and the first end of the second outer member 14 a second end of the first center member 20 is further pivotally coupled to the second end of the third outer member 16 and the first end of the fourth outer member 18 so as to extend between a juncture of the first and second outer members and a juncture of the third and fourth outer members similarly a second center member 22 having respectively opposed first and second ends thereof can also be provided with the present invention 10 the first end of the second center member 22 is pivotally coupled to the second end of the second outer member 14 and the first end of the third outer member 16 with a second end of the second center member 22 being pivotally coupled to the second end of the fourth outer member 18 and the first end of the first outer member 12 such that the second center member 22 extends between a juncture of the second and third outer members and a juncture of the fourth and first outer members as best illustrated in fig2 through 4 it can be shown that each of the ends.