earth mammal, earth dog, earth cat, earth horse, earth naysayer, earth bird {
  blood: warm;
}
earth mammal, earth dog, earth cat, earth horse, earth naysayer {
  produces-milk: true;
}
dog {
  says: "Woof!";
}
cat {
  says: "Meow.";
}
horse, naysayer {
  says: "Nay.";
}
[hey], ho {
  a: b;
}
ho {
  c: d;
}