Polarization of Light (2D) — Malus's Law & Polarizing Filters

This 2D companion drives the same Malus's Law physics as the 3D version — I = I0·cos²θ — through a plain canvas view built for reading the numbers rather than orbiting a scene: a side panel exposes both polarizer angles, an incident-intensity slider in real W/m² units, a wave-speed control, and buttons to switch the incoming light between linear, circular, and elliptical polarization. A live readout reports θ, cos²θ, the intensity after each polarizer in W/m², and the overall transmitted percentage, while a polar diagram traces the full cos²θ curve with a marker showing exactly where the current angle sits on it. You can also drag either polarizer directly in the canvas to rotate it.