OctaBall #2 Puzzle

Four pieces assemble into an “OctaBall”, my name for an Octahedron intersected with a sphere. This is my favorite version. The pieces have no symmetry and appear warped or tilted.  It is remarkable that they can assemble into a symmetrical shape.

WARNING: Assembly is challenging, you may even conclude that it is impossible! It is impossible if you add one piece at a time, but how else can you accomplish it?  Taking them apart can also be tricky, there are at least two ways to do it. One technique requires careful observation and good grip strength. OctaBalls are more difficult when all the pieces are the same color; I recommend using at least two colors.

Print two copies of piece A1 and two copies of M2, no supports are needed. The offset is 0.05 mm. Note that 4 copies of A1 will also assemble into an OctaBall, as will 4 copies of M2.  These assemblies are much easier.

Variations: I include pieces A1n and M2a. These can be swapped in for A1 and M2, these assemblies are more difficult.