code: function( bodyA, bodyB, bodyC, stiffness, targetAngle ){
  
              var cst;
  
              if (!bodyA || !bodyB){
  
                  return false;
              }
  
              cst = {
                  id: Physics.util.uniqueId('ang-constraint'),
                  type: 'ang',
                  bodyA: bodyA,
                  bodyB: bodyB,
                  bodyC: bodyC,
                  stiffness: stiffness || 0.5,
                  targetAngle: targetAngle || bodyB.state.pos.angle2( bodyA.state.pos, bodyC.state.pos )
              };
  
              this._angleConstraints.push( cst );
              return cst;
          }
docs: VerletConstraintsBehavior#angleConstraint( bodyA, bodyB, bodyC[, stiffness, targetAngle] ) -> Object
  - bodyA (Body): First body
  - bodyB (Body): Second body
  - bodyC (Body): Third body
  - stiffness (Number): A number between 0 and 1 that represents the stiffness of the constraint. Defaults to: `0.5`
  - targetAngle (Number): Target angle. Defaults to the current angle between bodies
  + (Object): The constraint data object
  
  Constrain three bodies to a target relative angle
  
  Returns constraint data that can be used to remove the constraint later.
  
  - `.bodyA`, `.bodyB`, and `.bodyC` are references to the bodies
  - `.type` is the type of constraint
  - `.id` is the string ID of the constraint
  - `.stiffness` is the stiffness
  - `.targetAngle` is the target angle