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:             let physicsId = Physics.getId tm.Id
              let shapeProperties =
                  { Center = Vector2.Zero
                    Friction = 0.0f
                    Restitution = 0.0f
                    FixedRotation = true
                    LinearDamping = 0.0f
  
negative.code:                           Radius = character'.Radius
                            Properties =
                              { Center = Vector2.Zero
                                Friction = 0.2f
                                Restitution = 0.0f
                                FixedRotation = true
                                LinearDamping = character'.LinearDamping
  