code: func Locate(tagged []tag.Token, rx *regexp.Regexp) [][]int {
  	rx.Longest() // make sure we find the longest possible sequences
  	rs := rx.FindAllStringIndex(quadsString(tagged), -1)
  	for i, ii := range rs {
  		for j := range ii {
  			// quadsString makes every offset 4x what it should be
  			rs[i][j] /= 4
  		}
  	}
  	return rs
  }
docs: // Locate finds the chunks of interest according to the regexp.