Geometry Blitz

How to play Geometry Blitz

1. Each card shows four colored shapes.
2. Use the legend on the left to see each shape’s “home color.”
3. If exactly one shape appears in its home color, that shape is the answer.
4. If no shape is in its home color, find the one shape whose shape and home color are both absent from the card — that shape is the answer.
5. If neither rule applies, then the card has no solution.
6. Press Show solution to reveal the answer and labels; press New card to play again.
7. You can also press keyboard keys: N for new card, S to show solution.

Geometry definitions

Polygons used in this game

• Triangle: a polygon with 3 sides and 3 angles.
• Pentagon: a polygon with 5 sides.
• Hexagon: a polygon with 6 sides.

Quadrilaterals (all 4‑sided polygons)

Quadrilateral means any polygon with four sides. The common families below may overlap (for example, every square is also a rectangle, a rhombus, and a parallelogram). We use the exclusive definition of trapezoid: exactly one pair of parallel sides.

• Kite: a quadrilateral with two pairs of adjacent equal sides. In this game our kites use two different pair-lengths, so they are not rhombi.
• Trapezoid: a quadrilateral with exactly one pair of parallel sides (the bases).
• Parallelogram: a quadrilateral with two pairs of parallel sides. Opposite sides are equal in length and opposite angles are equal.
• Rectangle: a parallelogram with four right angles.
• Rhombus: a parallelogram with all four sides equal in length. (Note: we purposely avoid rhombi in this game so a kite cannot also be a parallelogram.)
• Square: a rectangle and a rhombus (four equal sides and four right angles).

Game question: This game never generates a rhombus—kites have two pairs of adjacent equal sides of different lengths, and parallelograms have unequal adjacent side lengths. Why is this necessary?