<p>The <a href="https://en.wikipedia.org/wiki/Anson_Engine_Museum" class="extiw" title="w:Anson Engine Museum">Anson Engine Museum</a> in Poynton, Cheshire collection.
</p><p>The Otto patent specified 4 strokes- so designers attempted to design engines outside the patent. Samuel Griffin designed the <a href="https://en.wikipedia.org/wiki/Six-stroke_engine" class="extiw" title="w:Six-stroke engine">six-stroke engine</a> in 1883.
</p>
<ul><li>Induction</li>
<li>Compression</li>
<li>Ignition</li>
<li>Partial exhaust</li>
<li>Air blast</li>
<li>Complete exhaust</li></ul><dl><dd>That was 2 strokes doing nothing- to get around the patent</dd></dl><ul><li>In 1898 <a href="https://en.wikipedia.org/wiki/Dick,_Kerr_%26_Co." class="extiw" title="w:Dick, Kerr &amp; Co.">Dick Kerr of Kilmarnock</a> bought a Griffin patent to build a six stroke engine- two were made as Ottos patent lapsed in 1890.</li></ul>
Photograph by <a href="//commons.wikimedia.org/wiki/User:ClemRutter" title="User:ClemRutter">Clem Rutter, Rochester, Kent.</a> (<a rel="nofollow" class="external text" href="http://www.clemrutter.net/">www.clemrutter.net</a>).
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