There seemed to be a good amount of confusion in using accumulators to
print out the reverse of a string.  This combines a few advanced ideas
so let us try to break it down into its pieces.

First, when we accumulate a string, we are trying to "build up" the string
piece by piece.  In this case, we are trying to add one letter at a time from
a string.  The solution we had in class was:

<pre class=code>
reverse = ""
for i in range(len(word)-1, -1, -1):
    reverse += word[i]
print(reverse)
</pre>

Let's step through this one iteration at a time.  If we were to code this up
without the loop, we can see what is happening at each iteration

<pre>
#These are the initial steps
>>> word = "example"
>>> reverse = ""
>>> i = len(word)-1
>>> i
6
</pre>
So our loop starts with <tt>i</tt> having the value <tt>len(word)-1</tt>,
which is what we defined in our <tt>range</tt> function.  Now we'll start
accumulating:
<pre>
>>> reverse += word[i] #add the last letter in the word as the first letter
                       # of reverse
>>> reverse
'e'
>>> i = i-1  #one iteration is done, move on to the next value
>>> i
5
>>> reverse += word[i]
>>> reverse
'el'
>>> i = i-1
>>> i
4
>>> reverse += word[i]
>>> reverse
'elp'
>>> i = i-1
>>> i
3
>>> reverse += word[i]
>>> reverse
'elpm'
>>> i = i-1
>>> i
2
>>> reverse += word[i]
>>> reverse
'elpma'
>>> i = i-1
>>> i
1
>>> reverse += word[i]
>>> reverse
'elpmax'
>>> i = i-1
>>> i
0
>>> reverse += word[i]
>>> i = i-1
>>> i
-1
</pre>

Another solution to the problem constructs the loop in a more traditional way, 
but indexes differently:

<pre class="code">
reverse= ""
for i in range(1, len(word)+1):
    reverse += word[len(word)-1]
</pre>

The loop looks different, but the accumulation is the same:
<pre>
>>> word = "example"
>>> reverse = ""
>>> i = 1
>>> reverse += word[len(word)-i]
>>> reverse
'e'
>>> i=i+1
>>> reverse += word[len(word)-i]
>>> reverse
'el'
>>> i=i+1
>>> i
3
>>> reverse += word[len(word)-i]
>>> reverse
'elp'
>>> i=i+1
>>> i
4
>>> reverse += word[len(word)-i]
>>> reverse
'elpm'
>>> i=i+1
>>> i
5
>>> reverse += word[len(word)-i]
>>> reverse
'elpma'
>>> i=i+1
>>> i
6
>>> reverse += word[len(word)-i]
>>> reverse
'elpmax'
>>> i=i+1
>>> i
7
>>> reverse += word[len(word)-i]
>>> reverse
'elpmaxe'
>>> i=i+1
>>> i
8
>>> 
</pre>