A directional light and a spot light casting onto the same ground, side by side. It is the light's side of shadows: whether it casts at all, and the resolution, bias and softness underneath that.
Examples
Every one of these opens in the browser editor, running, with its node graph laid out for you to take apart. Nothing to install and no account needed.
One box, copied three times, each copy a different colour. It shows how a material node picks which objects it applies to, using the object index as its group, and how it points at a material by relative path.
mat/MeshBasic geo/Material
A box whose width, height, colour and display mode are five controls on a panel drawn over the viewer, plus a button that writes the box to a 3MF file. Built from spare params, with no UI code.
Object following the cursor
Animated
An object that follows the mouse across a plane. The cursor ray is built in the graph and intersected with that plane, then an actor moves the object there on every tick.
geo/Actor code/CursorRay code/Plane code/RayPlaneIntersect