OPTICS: light rays passing through lenses, bouncing off mirrors, and refracted by prisms. Animations of impossible lenses that change refractive index and curvature. Videos of additive colour mixing (RGB coloured lights) and subtractive colour mixing (CMYK coloured inks). Animations of polarization, lasers, and refraction in the human eye (refractive errors and their correction). Total internal reflection, fibre optics, and wave interference. Coloured wavelengths and spectra. Parabolic reflectors. Diverging lenses. Converging lenses. Corner cube reflectors. Doppler redshift and blue-shift.