Example of moving objects and checking for collisions. However, it can be cleaned up a bit, and it does not do any stepping!! meaning instances jump from point a to point b. So fast objects such a bullets may jump past walls.

CollisionUpdater.cs

	public class CollisionUpdater
	{
		List<IPhysics> components;
		public CollisionUpdater ()
		{
			components = new List<IPhysics> ();
		}
		
		public void AddComponent (IPhysics newComp)
		{
			components.Add (newComp);
		}
		
		public void RemoveComponent (IPhysics oldComp)
		{
			components.Remove (oldComp);
		}
		
		public void ReactCollisions ()
		{
			for (int i = 0; i < components.Count; i++) {
				IPhysics objA = components [i];
				objA.Move ();

				if (i < components.Count - 1)
					FindCollisionsWith (objA, i + 1);
			}
		}

		public void FindCollisionsWith (IPhysics objA, int fromIndex)
		{
			for (int j = fromIndex; j < components.Count; j++) {
				PhysicsComponent objB = components [j];
				if (objA.frame.Intersects (objB.frame)) {
					if (objA.ShouldIgnoreCollision (objB))
						continue;
					if (objB.ShouldIgnoreCollision (objA))
						continue;
					objA.Collision (objB);
					objB.Collision (objA);
				}
			}
		}
	}