code: function getClosestPoints( simplex ){
  
          // see http://www.codezealot.org/archives/153
          // for algorithm details
  
          // we know that the position of the last point
          // is very close to the previous. (by nature of the distance test)
          // this won't give great results for the closest
          // points algorithm, so let's use the previous two
          var len = simplex.length
              ,last = simplex[ len - 2 ]
              ,prev = simplex[ len - 3 ]
              ,scratch = Physics.scratchpad()
              ,A = scratch.vector().clone( last.pt )
              // L = B - A
              ,L = scratch.vector().clone( prev.pt ).vsub( A )
              ,lambdaB
              ,lambdaA
              ;
  
          if ( L.equals(Physics.vector.zero) ){
  
              // oh.. it's a zero vector. So A and B are both the closest.
              // just use one of them
              return scratch.done({
  
                  a: last.a,
                  b: last.b
              });
          }
  
          lambdaB = - L.dot( A ) / L.normSq();
          lambdaA = 1 - lambdaB;
  
          if ( lambdaA <= 0 ){
              // woops.. that means the closest simplex point
              // isn't on the line it's point B itself
              return scratch.done({
                  a: prev.a,
                  b: prev.b
              });
          } else if ( lambdaB <= 0 ){
              // vice versa
              return scratch.done({
                  a: last.a,
                  b: last.b
              });
          }
  
          // guess we'd better do the math now...
          return scratch.done({
              // a closest = lambdaA * Aa + lambdaB * Ba
              a: A.clone( last.a ).mult( lambdaA ).vadd( L.clone( prev.a ).mult( lambdaB ) ).values(),
              // b closest = lambdaA * Ab + lambdaB * Bb
              b: A.clone( last.b ).mult( lambdaA ).vadd( L.clone( prev.b ).mult( lambdaB ) ).values()
          });
      }
docs: hide
  getClosestPoints( simplex ) -> Object
  - simplex (Array): The simplex
  
  Figure out the closest points on the original objects
  from the last two entries of the simplex