:Class Penguin: Animal,BirdBehaviour,FishBehaviour
∇ R←NoCanFly
:Implements Method BirdBehaviour.Fly
R←'Although I am a bird, I cannot fly'
∇
∇ R←LayOneEgg
:Implements Method BirdBehaviour.Lay
R←'I lay one egg every year'
∇
∇ R←Croak
:Implements Method BirdBehaviour.Sing
R←'Croak, Croak!'
∇
∇ R←Dive
:Implements Method FishBehaviour.Swim
R←'I can dive and swim like a fish'
∇
:EndClass ⍝ Penguin