I received the tetrahedron 2 at the same time as the dual tetrahedron. It is a beautifully tactile shape with a lovely mixture of light and dark woods. Unlike the other puzzle it is impossible to see the seams where the 4 parts join. To open it there are only so many places to grab so it is just a matter of holding it in each hand and pulling apart. When you have the right orientation then it suddenly pulls partially open.
Pulling a little further allows the whole thing to just fall into 4 parts:
All in all a lovely and very satisfying puzzle.