docs: 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;
          }