centaur.rb

class Centaur
  attr_reader :name,
              :breed

  def initialize(name, breed)
    @name     = name
    @breed    = breed
    @actions  = 0
    @standing = true
  end

  def shoot
    if cranky? || laying?
      "NO!"
    else
      @actions += 1
      "Twang!!!"
    end
  end

  def run
    if cranky? || laying?
      "NO!"
    else
      @actions += 1
      "Clop clop clop clop!!!"
    end
  end

  def cranky?
    @actions > 2 ? true : false
  end

  def standing?
    @standing
  end

  def sleep
    standing? ? "NO!" : @actions = 0
  end

  def lay_down
    @standing = false
  end

  def laying?
    !standing?
  end

  def stand_up
    @standing = true
  end

end

medusa.rb

class Medusa
	attr_reader :name,
							:statues

	def initialize(name)
		@name 		= name
		@statues 	= []
	end

	def stare(victim)
		@statues << victim
		victim.stone
	end

end


class Person
	attr_reader :name

	def initialize(name)
		@name 	= name
		@stoned = false
	end

	def stone
		@stoned = true
	end

	def stoned?
		@stoned
	end

end

werewolf.rb

class Werewolf
  attr_reader :name, 
              :location, 
              :human

  def initialize(name, location="London")
    @name     = name
    @location = location
    @human    = true
  end

  def human?
    @human
  end

  def change!
    @human = !@human
  end

  def werewolf?
    !human
  end

end