Independently movable sole structure

1. An article of footwear comprising:

an outsole comprising a first outsole member centered at a first center position, the first outsole member including a first piece and a second piece;

a midsole comprising a protrusion structure corresponding to the first outsole member, the protrusion structure extending outward in a vertical direction from a base of the midsole, wherein the vertical direction is approximately normal to the base;

wherein the first piece is attached to the protrusion structure and wherein the first piece is centered at the first center position;

wherein the second piece is attached to the protrusion structure, the second piece is centered at the first center position, and the second piece surrounds the first piece;

wherein the first piece is spaced from the base by a first vertical distance, the first vertical distance being a distance in the vertical direction;

wherein the second piece is spaced from the base by a second vertical distance, the second vertical distance being a distance in the vertical direction;

wherein the first vertical distance is greater than the second vertical distance; and

wherein the first piece is separated from the second piece by a gap surrounding an entire periphery of the first piece and exposing the midsole in an entirety of the gap surrounding the periphery of the first piece.

2. The article of footwear according to claim 1 , wherein the gap extends vertically through the outsole along a side surface of the midsole.

3. The article of footwear according to claim 1 , wherein the protrusion structure comprises a first surface and a second surface, the first surface being spaced further from the base than the second surface;

wherein the first surface is within an inner edge of the second surface;

wherein the first surface is centered at the first center position and wherein the second surface is centered at the first center position;

wherein the first piece of the outsole is attached to the first surface of the midsole; and

wherein the second piece of the outsole is attached to the second surface of the midsole.

4. The article of footwear according to claim 3 , wherein the gap defines a horizontal separation distance;

wherein the horizontal separation distance extends along a horizontal direction and wherein the first vertical distance extends along a vertical direction, the vertical direction being perpendicular to the horizontal separation distance;

wherein a compression of the protrusion structure reduces a difference between the first vertical distance and the second vertical distance; and

wherein the first piece is spaced from the second piece by the horizontal separation distance during compression of the protrusion structure.

5. The article of footwear according to claim 1 , wherein the outsole further comprises a second outsole member centered at a second center position, the second outsole member including a third piece, a fourth piece, and a fifth piece;

wherein the third piece is attached to the midsole and wherein the third piece is centered at the second center position;

wherein the fourth piece is attached to the midsole and wherein the fourth piece is centered at the second center position;

wherein the fifth piece is attached to the midsole and wherein the fifth piece is centered at the second center position; and

wherein the third piece is configured to be elastically separated from the fourth piece and from the fifth piece.

6. The article of footwear according to claim 1 , wherein the protrusion structure has a stepped surface.

7. The article of footwear according to claim 1 , wherein the first piece is operable to move independently of the second piece in the vertical direction.

8. The article of footwear according to claim 1 , wherein the first piece is operable to move independently of the second piece in a horizontal direction.

9. The article of footwear according to claim 1 , further comprising a sipe disposed between the first piece and the second piece.

10. The article of footwear according to claim 9 , wherein the sipe surrounds the first piece.