/***
 * Square Root Function
 *
 * Gets the square root of a number (within a margin of error)
 *
 * Useful for diagonal/Pythagorean stuff.
 *
 * scss:
 *   sqrt($num)
 *
 * @param $num - number to get square root of
 */
@function approximateSq($num, $approx) {
  $root : (( $num / $approx ) + $approx) / 2;
  @return $root;
}
@function sqrt($num) {
  $unit: $num / stripUnits($num);
  $root: 1;
  $num: stripUnits($num);
  $upperBounds : ($num / 2) + 1; //never need over half the main number. Add one just to be sure!
  $loops : $upperBounds;
  @if $num >= 4 {
    @for $test from 2 through (round($upperBounds)) {
      $sq : $test * $test;
      @if $sq <= $num {
        $root : $test;
      }
    }
  }
  @else {
    $test: 1.1;
    @while $test < $upperBounds {
      $sq : $test * $test;
      @if $sq <= $num {
        $root : $test;
      }
      $test: $test + .1;
    }
  }

  // increase accuracy
  @for $i from 1 through 2 {
    $root : (approximateSq($num, $root));
  }

  @return $root * $unit;
}