1. flach   pentagon   segment   plane   heptagon   Hint Half-n-half Clue   2. Viereck   ellipse   pentagon   quadrilateral   concave   Half-n-half Clue   3. Vieleck   plane   straight line   parallelogram   polygon   Half-n-half Clue   4. Segment   segment   perpendicular lines   convex   plane   Half-n-half Clue   5. Pentagon   pentagon   prism   pyramid   parallel lines   Half-n-half Clue   6. Konkav   hexagon   oval   parallel lines   concave   Half-n-half Clue   7. Gipfel   ray   segment   vertex   plane   Half-n-half Clue