This puzzle is simply a modified triumph, with each piece having an extra prism block attached on one end to make a "hook" that wraps around the neighboring piece. This puzzle has two solutions -- for one of them these hooks cause quite a headache because they make assembly and disassembly possible only though simultaneous motion of all six pieces along all of the four-fold axes at once. This is called coordinate motion, and it is very cool. Once the puzzle is assembled in this preferred configuration, the tendency is to avoid disassembly at all costs. Of course this is often thwarted because the puzzle is so much fun to expand and contract that inevitably the puzzle expands far enough for the pieces to all fall apart. This is usually a good time to try the other solution which is difficult too and requires coordinate motion of three pieces to get each of the two halves together.