anchor.diff:                          { Radius = avatar'.Size.X * 0.5f
                             Properties =
                               { Center = Vector2.Zero
  -                              Friction = 0.0f
  +                              Friction = 0.2f
                                 Restitution = 0.0f
                                 FixedRotation = true
                                 LinearDamping = avatar'.LinearDamping
  
positive.code:                     { Extent = block'.Size * 0.5f
                        Properties =
                          { Center = Vector2.Zero
                            Friction = 0.0f
                            Restitution = 0.0f
                            FixedRotation = false
                            LinearDamping = 5.0f
  
negative.code:             let physicsId = Physics.getId tm.Id
              let shapeProperties =
                  { Center = Vector2.Zero
                    Friction = 0.2f
                    Restitution = 0.0f
                    FixedRotation = true
                    LinearDamping = 0.0f
  