One can also divide the period of a glider stream in half by using a combination of guns to insert gliders into the gaps of a higher period stream. In this case, the gun itself has a strictly higher period than its output stream, which is why the term pseudo is used. Note, however, that it produces the same output stream as a proper gun of the same periodicity.
Several years ago, the first pseudo period-15 glider gun was constructed by Dean Hickerson, using a glider turning reaction discovered by David Buckingham. Recently, this problem was revisited by David Buckingham, who constructed a smaller gun, which is included in the most recent pattern archive. The picture above shows an even smaller version of the pattern, constructed in October '95 by Dean Hickerson. A pattern file that can be run in a Life simulation program is linked to the picture.
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