Radix tree ASCII printing.
[r] -> [ou]
           `-(o) [m] -> [au]
                         `-(a) [n] -> [eu]
                                       `-(e) []=0x0
                                       `-(u) [s] -> []=0x1
                         `-(u) "lus" -> []=0x2
 `-(u) [b] -> [ei]