This Demonstration explores Stokes parameters, polarization spheres, and polarization ellipses for the superposition of two slightly noncollinear polarized light beams. The polarization vectors of the two beams are given by and , while their amplitudes are and . The Stokes parameters are designated by the curves (thick black), (dashed blue), (dotted green), and (dot-dashed red). The polarization ellipse is calculated for a user-controlled point shown as a vertical line on the Stokes-parameter plot and as a black point on the polarization-sphere plot.