I got curious about a single stroke engine design that popped into my head and made the attached animation. . It does not look to me like it would have any use but curiosity value. In fact it does not appear to have any redeeming features whatsoever - two crankshafts that speed up and slow down so gearing cannot connect them, valving would be horrendous, it just doesn't look like it would be efficient etc etc. However it should work, and it can sort of be said to to be One-stroke, "sort of" probably being a very important qualification. Note that the animation is with the left hand crank running at a constant rotation and that the right hand crank speeds up and slows down during one rotation. I have searched the net looking for anything similar but can't find anything. Has anybody seen similar and what are they called?