Christmas Lights: Series vs Parallel Circuits (3D)

A real string of Christmas light bulbs, wired either in series (one shared loop) or in parallel (each bulb its own branch across the source), solved live with Kirchhoff's voltage and current laws. Toggle the wiring, adjust the bulb count, source voltage and bulb resistance, and click any bulb in the 3D scene to burn it out — in series the whole string goes dark because the loop is broken, while in parallel only that bulb goes dark because every other branch still has its own path back to the source. Each bulb's brightness is driven by its own computed electrical power, not a scripted on/off state.