 Its key structural feature was an A-frame which carried wire braced wings and linked to a flat girder rear fuselage.It later evolved through the Schneider Grunau 9 into the very popular Zögling, which avoided the controversial "skullsplitter" forward member of the A-frame with a vertical strut behind the pilot, and was related to the secondary RRG Prüfling glider that replaced wire bracing with rigid lift struts.The Hols der Teufel of 1928, designed by Lippisch and Hans Jacobs, possibly with the assistance of Alexander Schleicher had the Zögling girder frame and the strut braced wings, making it very different from its ancestral namesake.