Various illumination and viewing geometries in a planet-ring system simulated with Pryngles. The star (white dot) and planetary orbit are not to scale. The circular planetary orbit has an inclination angle i of 60°. The ring has an inclination angle γ of 70° and a roll angle λ_r of 0° (this system is thus mirror-symmetric from left to right). The true planetary anomaly ν is shown next to each planet image and increases rotating counterclockwise. The colors of the spangles in this figure are indicative of viewing and illumination conditions, following the conventions explained in the text.