A capacitive sensor electrode pattern comprises a plurality of sensor electrodes. The plurality of sensor electrodes are disposed in a common layer with one another and arranged to form an ellipse. The plurality of sensor electrodes comprises first, second, and third subsets of sensor electrodes. The first subset of sensor electrodes has a first shape and a first surface area, wherein centers of mass of the first subset of sensor electrodes are substantially coincident with nodes of a coordinate system. The second subset of sensor electrodes has a second subset of sensor electrodes has a second shape and a second surface area. The third subset of sensor electrodes has a third shape and a third surface area. The first, second, and third shapes are all different. The first, second, and third surface areas are all different, and the second and third surface areas are less than the first surface area.