 understand the problem here. Interestingly, it 
&gt; doesn't bother
&gt; &gt;me too much. Let me explain.
&gt; &gt;
&gt; &gt;MW: Until recently I used as my baseline a viewpoint that 
&gt; said that there
&gt; &gt;were individual things like you, my car, classes, and 
&gt; associations, where
&gt; an
&gt; &gt;association is a relationship that understands that it lasts 
&gt; for a period
&gt; of
&gt; &gt;time. I have moved to a 4D approach, replacing individual things with
&gt; &gt;spatio-temporal extents,