1. linee perpendicolari   quadrilateral   parallelogram   perpendicular lines   pentagon   Hint Half-n-half Clue   2. ovale   parallel lines   vertex   oval   quadrilateral   Half-n-half Clue   3. piramide   convex   perpendicular lines   ellipse   pyramid   Half-n-half Clue   4. prisma   prism   convex   concave   pentagon   Half-n-half Clue   5. raggio   straight line   hemisphere   ray   concave   Half-n-half Clue   6. concavo   ellipse   concave   hemisphere   hexagon   Half-n-half Clue   7. linee parallele   parallel lines   segment   pentagon   quadrilateral   Half-n-half Clue