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Size := Object clone
large := Size new
medium := Size new
small := Size new

Colour := Object clone
black := Colour new
brown := Colour new
white := Colour new

Dog := Object clone do(
  size := medium
  color := brown
  
  bark := method(
    "arf! arf!" println
  )
)

tucker := Dog clone do(
  size = small
  bark = method("ah! ah!" println)
)