Update 23 October 2017 - Dear Reader, please check out my new puzzle blog and e-store at http://mechanical-puzzles.com
These two puzzles came from IPP34. The Cast Metal Puzzle (cube) was Markku Vesala's Exchange Puzzle while the Brass Ball was purchased from Dmitry Pevnitskiy during the Puzzle Party.
The Brass Ball is a co-ordinate motion puzzle. Relatively easy to take apart (with some pressing and tugging here and there) but a real bummer to reassemble.
Somehow every time I think I have all the pieces in position ready to slide back together, something will be stuck, not to mention its really difficult to operate all the 4 pieces at the same time. When Dmitry demonstrated the Brass Ball to me at IPP, he could put it back together in a matter of seconds!
I am still struggling with this one and it remains on my table in 4 separate pieces. If anyone has the solution to this, please help, thanks.
Edit: 7.5 hours later, I played with the Brass Ball again and after a while of fiddling, got it assembled.
The Cast Metal Puzzle #81/125 on the other hand is easier. Comprising 6 pieces of tetraminoes and pentaminoes, the pieces are "interlocked" together by a magnetic ball bearing in the centre.
Nice concept, very well made and high quality. Being cast iron, its also very heavy in the hand for such a small puzzle measuring only 3cm square.