Hi Lark Work, Steve and folks,

You define the SomeDataProcessing class within Shoes.app block.

But even in the Shoes.app block, you can't use Shoes methods (ex. stack,
edit_box, etc.) directly in the SomeDataProcessing class. As same as the
following snippet:

--------------
class A
  def a
    puts 'hi'
  end
end

def m
  a
end

m  #=> undefined local variable or method `a'
--------------

So, try this out: https://gist.github.com/866935

Hope this helps,
ashbb