Not really a mnemonic in German, but I once learned how to remember of the moon was in first or third quarter by comparing the form of the crescent with the Vereinfachte Ausgangsschrift cursive letters “a” (abnehmender Mond, first quarter crescent) and “z” (zinehmender Mond, third quarter crescent). The same applies to screws watching from the top, cursive “a” is for “auf” (open) and “z” for zu (close). By reading the comments, this is somewhat the closest you get to your mnemonic.