1. concave   parallelogram   concave   ray   straight line   Hint Half-n-half Clue   2. pyramide   quadrangle   oval   straight line   pyramid   Half-n-half Clue   3. hémisphère   vertex   ray   hemisphere   rhombus   Half-n-half Clue   4. parallélogramme   parallelogram   convex   concave   pyramid   Half-n-half Clue   5. lignes perpendiculaires   perpendicular lines   parallel lines   hemisphere   oval   Half-n-half Clue   6. lignes parallèles   pyramid   polygon   perpendicular lines   parallel lines   Half-n-half Clue   7. Heptagon   heptagon   quadrangle   pyramid   parallelogram   Half-n-half Clue