Short Version

• Arrange the puzzle pieces to form a convex shape without overlapping.
• Drag pieces around the grid; use the buttons below to rotate and flip them.
• Each convex shape you find will be captured in the “trophy boxes” to the right.
• Find as many different shapes as you can!

What is a convex shape? What shapes are accepted?

Imagine a rubber band closing around the shape. The shape is convex if the band snaps tight against every edge. If the band leaves any gaps, then the shape is not convex.

The three colorful examples at the top of the page are not convex. The four below are convex, although they use pieces from a different puzzle.

Read more about convex polygons at at Mathworld or at Math Open Reference

More Details and Fine Print

• Pieces always snap to the grid, with their vertices at grid points.
• Rotations are only in 60° increments, so some orientations of the pieces are not possible.
• You can use the r, d, and f keys to rotate and flip, if you have a keyboard.
• I know of twelve different convex shapes. Maybe you'll find a thirteenth?
• You can also just play with the pieces and build shapes however you like.