docs: function getSimiliarString(base, relation) {
  	var length = Math.round(base.length * relation),
  		r = '',
  		i, str
  	do {
  		str = getRandomString(base.length - length)
  	} while (str && str[0] === base[length])
  	for (i = 0; i < length; i++) {
  		r += base[i] // substr(...) seems to be optimized
  	}
  	return r + str
  }