k of issues
&gt; &gt; &gt; of rate of wear of machine parts. Even biologists have to think about
&gt; &gt; &gt; cumulative error rates in DNA replication.
&gt; &gt; &gt;
&gt; &gt;   Yes, I left out the implied qualifier in the phrase, it should
&gt; &gt;have been: "multiple reiterative processes **involving vague
&gt; &gt;concepts like a heap** . . .".  The types of physical reiterative
&gt; &gt;processes you mention present no problem because the systems
&gt; &gt;are among those "just about every practical