Funck Rotary made a small two-stroke radial engine with exhaust-flow by other piston cylinders as we see in the following illustrations. It does not lack a certain complexity.

"New image of the old Funck"

“Funck rotary engine”

From Appendix 9: We located another variant of this special radial engine, perhaps in more detail now.

-It has more detail about the connecting rods, which are very short though. The cylinder has a counter-piston with a hole for the spark plug on the cylinder head.

-But attention is drawn to ducts that connect the cylinder bases to propagate the ignition.

-It seems that intermediate sleeves are rotating. In the main text it is already commented that it is a complex engine, and it is worth looking for more information.