A well known engineer and dirttrack-racer G.A. Mangoletsi designs and tests in 1930 a desmodromic system. Both cams are closely positioned to one another and work on the same kneeformed rocker. A platespring helps overcome the necessary lash. Ref.: H. Hütten in “Schnelle Motoren”, p. 105.
Setwright in “Valve Gear for High Speed Internal Combustion Engines”, p. 136
[Classification = hard to tell: in our desmobook we mention this a very special Group 6 A design, but now I would rather go for Group 7 B]