docs: function _rotateRadian(radiansRaw, radialAdj) {
    radialAdj %= TWOPI;
  
    return _.map(radiansRaw, function(r){
      r += radialAdj;
  
      // for radial positions that cross the baseline, recompute
      if(r > TWOPI) { return r -= TWOPI; }
      if(r < 0) { return r += TWOPI; }
  
      return r;
    });
  }