code: function cat() {
          return reduce(arguments, function(result, seq) {
              if (!arrayp(result))                 result = slice(result)
              if (!arrayp(seq) && sequencep(seq))  seq    = slice(seq)
  
              return result.concat(seq) })
      }
docs: /// Function cat /////////////////////////////////////////////////////////  (seq[, seqs...]) ↦ Array  Returns an array with the given sequencess concatened.