anchor.diff:          abstract Life : Life with get, set
   
       /// A particle constraint.
  -    type [<StructuralEquality; NoComparison; CompilationRepresentation (CompilationRepresentationFlags.UseNullAsTrueValue)>] Constraint =
  +    type [<NoEquality; NoComparison; CompilationRepresentation (CompilationRepresentationFlags.UseNullAsTrueValue)>] Constraint =
           | Rectangle of Vector4
           | Circle of single * Vector2
           | Constraints of Constraint array
  -        | Unconstrained // OPTIMIZATION: elide Option indirection
  +        | NoConstraint // OPTIMIZATION: elide Option indirection
   
           static member (+) (constrain, constrain2) =
               match (constrain, constrain2) with
  -            | (Unconstrained, Unconstrained) -> constrain // OPTIMIZATION: elide Constraint ctor
  -            | (_, Unconstrained) -> constrain
  -            | (Unconstrained, _) -> constrain2
  +            | (NoConstraint, NoConstraint) -> constrain // OPTIMIZATION: elide Constraint ctor
  +            | (_, NoConstraint) -> constrain
  +            | (NoConstraint, _) -> constrain2
               | (_, _) -> Constraints [|constrain; constrain2|]
   
       /// The output of a particle behavior.
  
positive.code: 
      /// Transforms a particle value.
      type 'a Transformer =
          single -> 'a -> struct ('a * Output)
  
      [<AutoOpen>]
      module Transformer =
  
          /// Pipe two transformers.
          let pipe (transformer : 'a Transformer) (transformer2 : 'a Transformer) : 'a Transformer =
              fun progress a ->
                  let struct (a, output) = transformer progress a
                  let struct (a, output2) = transformer2 progress a
                  struct (a, output + output2)
  
          /// Pipe multiple transformers.
  
negative.code:     type Behavior =
  
          /// Run the behavior.
          abstract Run : int64 -> Constraint -> obj -> (obj * Output)
  
      /// Defines a particle behavior.
      type [<NoEquality; NoComparison>] Behavior<'a, 'b when 'a : struct> =
  