function main ()

	-- get the scene in the global scope --
	scene = Scenes.get("World")
	
	-- load up a sphere --
	scene:import("samples/shapes/shapes.xsg:Sphere")
	
	-- get a reference to the sphere's transform --
	sphere_transform = Resources.getTransform("Sphere");
	
	-- get a reference to the sphere's geometry --
	sphere_geometry = Resources.getGeometry("SphereShape");
	
	
	
	-- make a new entity to represent our physical sphere --
	entity = Entities.create("PhysicalSphere");
	
	-- Bind this entity with our sphere's transform. --
	-- We do this because the physics simulation     --
	-- affects the transform in order to move the    --
	-- sphere around.                                --
	entity:bind(sphere_transform);
	
	-- enable physics on the entity --
	Entities.enablePhysics(entity);
	
	
	
	-- set the physical sphere's geometry for collision --
	Entities.physicalGeometry(entity):useMesh(sphere_geometry);
	
	
	
	-- Create and bind a new script which will continually --
	-- update the physical sphere entity.                  --
	-- This script is included with Geos, click here to    --
	-- see what it looks like.                             --
	script = Scriptsystem.bindScript("utility/scripts/physics_updater.lua", entity);
	
	-- Start the script --
	Scriptsystem.startScript(script);
	
end