Foo
  can baz, speak, and glark.
  kids must speak
  uses Whuffle
  Bar
    has length of 10, breadth of 10, snickerer of only 0 or 1, and weight matching "^\d+".
    can mutate returning Mutator, breed returning Breeder, and teleport.
  Glark 
    can yodel loudly or softly, sing. 
    inherits Traits::Charm.