Try entering your problem into boxes A, B, C, D and D' as continuations of sentences. You will see the result in yellow boxes and the solution in green-bordered box in the middle. When your statements are clear, all the sentences in yellow boxes should look valid, relevant and true. Play till sentences make sense and then you will be able to work out E and good solution. Arrows between boxes mean necessities ("in order to A, you need B"), not causes.
Based on the ideas of great business semiotic and ToC expert Jelena Fedurko