useHelperGrid and useHelperAxis draw a floor and the axes, and each crate carries a gizmo that turns with it. screenToRay turns the pointer into a ray in the world: met with the floor it places the white cross, and tested against the crates it picks one, which useHelperLines outlines.
The crates are found by name with findObjects, and the camera circles with cameraLookAt keeping the middle in view.