anchor.diff:  
           static member internal setEntityBounds (value : Vector4) entity world =
               let mutable transform = &(World.getEntityState entity world).Transform
  -            World.setEntityTransform { transform with Position = v2 value.X value.Y; Size = v2 value.Z value.W } entity world
  +            let position = value.Xy
  +            let size = value.Zw
  +            if transform.Position <> position || transform.Size <> size
  +            then World.setEntityTransform { transform with Position = position; Size = size } entity world
  +            else world
   
           static member internal getEntityCenter entity world =
               let mutable transform = &(World.getEntityState entity world).Transform
  
positive.code: 
          static member internal setEntityCenter value entity world =
              let mutable transform = &(World.getEntityState entity world).Transform
              World.setEntityTransform { transform with Position = value - transform.Size * 0.5f } entity world
  
          static member internal getEntityBottom entity world =
              let mutable transform = &(World.getEntityState entity world).Transform
  
negative.code:                         let oldEntityState = entityState
                          let oldOmnipresent = oldEntityState.Omnipresent
                          let oldAbsolute = oldEntityState.Absolute
                          let oldBoundsMax = if not oldEntityState.Omnipresent then World.getEntityStateBoundsMax oldEntityState else v4Zero
                          let world = World.setEntityState entityState entity world
                          let world = World.updateEntityInEntityTree oldOmnipresent oldAbsolute oldBoundsMax entity oldWorld world
                          let world = facet.Register (entity, world)
  