code: function(elem, delta) {
          var pi = Math.PI, pi2 = pi * 2;
          var ch = function(t) {
              var a =  (t < 0)? (t % pi2) + pi2 : t % pi2;
              return a;
          };
          var tt = this.theta, et = elem.theta;
          var sum, diff = Math.abs(tt - et);
          if(diff == pi) {
            if(tt > et) {
              sum = ch((et + ((tt - pi2) - et) * delta)) ;
            } else {
              sum = ch((et - pi2 + (tt - (et)) * delta));
            }
          } else if(diff >= pi) {
            if(tt > et) {
              sum = ch((et + ((tt - pi2) - et) * delta)) ;
            } else {
              sum = ch((et - pi2 + (tt - (et - pi2)) * delta));
            }
          } else {  
            sum = ch((et + (tt - et) * delta)) ;
          }
          var r = (this.rho - elem.rho) * delta + elem.rho;
          return {
            'theta': sum,
            'rho': r
          };
      }
docs: /*
  Method: interpolate
  
  Calculates a polar interpolation between two points at a given delta moment.
  
  Parameters:
  
  elem - A <Polar> instance.
  delta - A delta factor ranging [0, 1].
  
  Returns:
  
  A new <Polar> instance representing an interpolation between _this_ and _elem_