sure you base
things on each other. If you mention an aspect during the problem statement,
make sure you will show a solution for it later. If you can't, it's probably
better to leave that aspect out of your talk. Not every aspect has to run
as a thread through the whole talk. For example, if you introduced a hallmark
feature in the second part and it has a really interesting implementation
detail, by all means, introduce that by the end, even if it doesn't
specifically relate to the problem.</p>
<p>Do not 