3D Cubic fractal

This is a 3D fractal made for a math project with the 123D Design Software. The base is a cube from which each face is divided in order to obtain a tiling pattern of 5 diamonds with the same area. On each face, the middle diamond is kept and the 4 others around the middle one are extruded in the 3D modeling software. The pattern is repeated in the middle diamond. For this project, the pattern was repeated 3 times. However, I encountered a problem which i was not able to fix. If you look at the bottom face of the cube, two of the second level pattern diamonds did not want to be extruded properly. The rest of the cube is finished.