Octahedron. 6 raisins, 12 toothpicks. 8 triangles, 3 squares.

This is the second simplest regular solid. It is also satisfyingly rigid. If you join the midpoints of the triangles you get a cube. That means the octahedron is dual to the cube.

Looking at it from different directions you can see a square or a hexagon, just like a cube.