Spark
I rewrote it in C, so it's faster and can work more efficiently on different data sets. It also uses a prettier algorithm for determining heights. Have fun:<p><a href="http://git.zx2c4.com/spark/tree/spark.c" rel="nofollow">http://git.zx2c4.com/spark/tree/spark.c</a><p><pre><code>    $ git clone http://git.zx2c4.com/spark
    $ cd spark
    $ make
    $ ./spark 1 4 2 8 14
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    $ curl -s http://earthquake.usgs.gov/earthquakes/catalogs/eqs1day-M1.txt | cut -d, -f9 | ./spark
    ▂▃▄▃▃▃▄▃▇▃▄▄▄▅▃▄▄▄▅▅▅▄▄▄▃▃▃▃▃▄▃▄█▅▄▄▄▄▃▇▄▄▄█▄▃▄▄▄▄▃▃▄▅▄▅▃▃▃▃▇▄▅▄▇▃▅▃▄▃▄▃▇▃▃▄▇▃▄▃▄▃▃▃▄▃▃▃▃▃▃▅▃▄▃▃</code></pre>