1. 頭頂　   rhombus   polygon   vertex   convex   Hint Half-n-half Clue   2. 区切り、部分   hexagon   quadrangle   oval   segment   Half-n-half Clue   3. 四辺形   parallel lines   quadrilateral   plane   perpendicular lines   Half-n-half Clue   4. 七角形   heptagon   pentagon   segment   parallel lines   Half-n-half Clue   5. 六角形   polygon   convex   hexagon   hemisphere   Half-n-half Clue   6. 多角形   perpendicular lines   plane   polygon   hexagon   Half-n-half Clue   7. 平行四辺形   oval   quadrilateral   convex   parallelogram   Half-n-half Clue