A while back Rowland Manufacturing Company in New Washington Ohio advertised model engine castings in just one issue of Home Shop Machinist magazine. Normally I do not buy castings, but these looked kind of unique and the price was reasonable. I believe it was a college student using his new computer design skills to design engines, same as POWDER KEG does. He had done a lot of work and had designs so the engine could be made into any kind of piston engine, gas, steam vacuum, etc. He sold the castings and plans separately. In order to maintain a little personal identity of my own I just ordered castings and made my own plan. When the castings arrived, in order to get more than my money's worth, I used the castings as patterns and poured a send set. One engine was fitted with an eccentric and a spool valve. The other with poppet valves. They are also timed to run on opposite directions.
Nothing spectacular, just more engines to look at.