Rhombus
When constructing rhombus ABDC, I started with circle A and copied it four times so that they all were congruent. I then moved the circles so that the center of C circle was the radius for circle A and D, the the circle D had the radius C and B, and the circle B had radius D and A. Next, I created segments AB, BD, DC, and CA with the radii of the circles. Then, I created the diagonals AD and CB and proved that they were perpendicular with the circles C and B, and D and A because they're perpendicular bisectors. Since the sides are congruent and the diagonals are perpendicular bisectors ABDC is a rhombus.