code: function( coef ){
  
              var constraints = this._distanceConstraints
                  ,scratch = Physics.scratchpad()
                  ,BA = scratch.vector()
                  ,con
                  ,len
                  ,corr
                  ,proportion
                  ;
  
              for ( var i = 0, l = constraints.length; i < l; ++i ){
  
                  con = constraints[ i ];
  
                  // move constrained bodies to target length based on their
                  // mass proportions
                  BA.clone( con.bodyB.state.pos ).vsub( con.bodyA.state.pos );
                  len = BA.normSq() || Math.random() * 0.0001;
                  corr = coef * con.stiffness * ( len - con.targetLengthSq ) / len;
  
                  BA.mult( corr );
                  proportion = (con.bodyA.treatment !== 'dynamic' || con.bodyB.treatment !== 'dynamic') ? 1 : con.bodyB.mass / (con.bodyA.mass + con.bodyB.mass);
  
                  if ( con.bodyA.treatment === 'dynamic' ){
  
                      if ( con.bodyB.treatment === 'dynamic' ){
                          BA.mult( proportion );
                      }
  
                      con.bodyA.state.pos.vadd( BA );
  
                      if ( con.bodyB.treatment === 'dynamic' ){
                          BA.mult( 1 / proportion );
                      }
                  }
  
                  if ( con.bodyB.treatment === 'dynamic' ){
  
                      if ( con.bodyA.treatment === 'dynamic' ){
                          BA.mult( 1 - proportion );
                      }
  
                      con.bodyB.state.pos.vsub( BA );
                  }
  
                  con.bodyA.sleepCheck();
                  con.bodyB.sleepCheck();
              }
  
              scratch.done();
          }
docs: internal
  VerletConstraintsBehavior#resolveDistanceConstraints( coef )
  - coef (Number): Coefficient for this resolution phase
  
  Resolve distance constraints.