earth mammal, earth horse, earth naysayer, earth cat, earth dog, earth bird {
  blood: warm;
}

earth mammal, earth horse, earth naysayer, earth cat, earth dog {
  produces-milk: true;
}

dog {
  says: "Woof!";
}

cat {
  says: "Meow.";
}

horse, naysayer {
  says: "Nay.";
}

[hey], ho {
  a: b;
}

ho {
  c: d;
}

fancy outer space vehicle, fancy outer space new american mars rover, new american mars fancy outer space rover {
  insides: advanced;
}

new american mars rover {
  wheels: big;
}

foo, a b c {
  something: whatever;
}

a b c {
  blah: blah;
}

d e f, d e g {
  blah: blah;
}

g {
  bloo: bloo;
}