1. へいめん   plane   perpendicular lines   polygon   rhombus   Hint Half-n-half Clue   2. ちょうえん   parallelogram   ellipse   convex   rhombus   Half-n-half Clue   3. へいこうしへんけい   hexagon   straight line   parallelogram   ellipse   Half-n-half Clue   4. こうせん   plane   ray   parallel lines   hemisphere   Half-n-half Clue   5. ちょくせん   straight line   polygon   heptagon   rhombus   Half-n-half Clue   6. おうめん   polygon   hexagon   concave   ellipse   Half-n-half Clue   7. しちかっけい   convex   concave   heptagon   quadrangle   Half-n-half Clue