def describe(obj)
    case obj
    when Numeric
        puts "obj is number"
    when String
        puts "obj is string"
    when Tiger
        puts "Tiger age is #{obj.getAge()}"
    else
      "unknown"
    end
end

class Tiger
    def initialize(age)
        @age = age
    end

    def getAge()
        @age
    end
end
result = describe(Tiger.new 15)
puts result