Trouble Combining Repeats and Closing Bars in tunes

Hi,

I am looking at a 4 - part tune where the first and third parts are
repeated and the second and fourth parts are not repeated. Try as I
may, I cannot get Lilypond to put  the repeats and closing bars in the
right place when engraving the tune. The following is just about as
simple as I can get it and still show the issue.  

% BarExample.ly
\version "2.19.48"

example = {   \time 2/4
\relative c''{
\repeat volta 2 { a8 a8 a8 a8 | a8 a8 a8
a8 | \break  }
\bar ".|" d8 d8 d8 d8
|  d8 d8 d8 d8 | \bar "|." \break
\repeat volta 2 { a8 a8 a8 a8 | a8 a8 a8
a8 | \break }
\bar ".|"  d8 d8 d8 d8 |
d8 d8 d8 d8 | \bar "|." \break }
}

\score
{
\new Staff <<

\new Voice {
\example
}
>>
}
% end BarExample.ly

This produces the following which is clearly not what I intended since
the first and third lines should be repeated and the second and fourth
lines are not repeated.

What am I doing wrong and what is the best way to fix it short of
using separate score blocks for each part?


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