My L(8)tice-2 interlocking burr design came about after I saw Andrei Ivanov from Russia selling copies of his Lattice Xi-2 on his metal puzzles site Mertallofactua. Andrei’s Lattice Xi-2 is an “enhanced version of the ξ-Lattice by Yoshiyuki Kotani with all six parts being different”. The Lattice Xi-2 is a 6 piece board burr and requires 3 steps to remove the first piece. Beautifully made out of polished matt stainless steal.
I decided to up the ante and see if I could come up with an 8 piece version with a (higher) unique solution. After several days of toying with Burr Tools, I managed to design a version, L(eight)tice-2 having a level 5.1.2 single solution. I contacted Andrei and told him about my design and asked if he would consider making copies of L(eight)tice-2 in aluminium. There were several exchanges of Facebook messages and Andrei agreed to cut a prototype out of 5mm aluminium sheet. This was several weeks before IPP37 in Paris in August. Andrei said he would try to have the prototype ready and show it to me at IPP.
On the Awards Night Banquet of IPP37, Andrei walked over to my table and plonked this heavy hefty aluminium L(eight)tice-2 down. It was pretty massive at 70mm x 70mm x 40mm! I played with it for a while but very gently. I did not want to unravel the pieces as I knew I wouldn’t be able to put everything back together at the dinner table without help. It felt fairly stable and none of the pieces dropped out even after being shaken pretty hard. This prototype was returned to Andrei and he said he would try experiment with 3mm thick stainless steal to produce a smaller sized puzzle. Andrei later reported that another attendee at IPP37 solved the puzzle by hand without too much difficulty. Well, kudos to him for being such a good solver.
After I returned home from IPP, I tried to improve on my design; unfortunately there is only so much one can do with board burr pieces confined to dimensions of 70mm x 40mm. But after quite a fair amount of tweaking, I did manage to increase the level of difficulty from Level 5.1.2 to a Level 18.104.22.168. However the downside was that I could not get it down to a unique solution. So this latest version would have 2 solutions, one Level 5, the other Level 6. The Level 6 solution with 13 steps (on paper at least) seems to indicated that the whole ensemble would be harder to solve and also appearing even more stable than the earlier version.
I subsequently dropped Andrei a note about this second iteration of my design and when the time came to produce copies in stainless steal, he adopted my “improved” design ie L(8)tice-2. While waiting for his metal puzzle, I decided to cut a copy out of acrylic. The plastic version confirmed my theory above; fitting pretty snugly together and harder to solve. A couple of weeks later, Andrei finished producing his copies and listed them for sale on his site. He had experimented with various tolerances and the copy I received from him was firm and “tight”. The puzzle feels very solid and heavy in the hand and no way would the pieces be shaken loose unless it was violently thrown to the floor. My copy of L(8)tice-2 had nicely rounded corners and polished to a smooth matt surface, very nice to the touch. Very good construction and high quality indeed. At either level, the L(8)tice-2 is not an easy puzzle and I still cannot solve it without the aid of Burr Tools. And I must add that it is quite a challenge to handle all 8 pieces at the same time during assembly! Metal interlocking burr puzzles are rare and hard to come by. I am really delighted that Andrei Ivanov has made available the L(8)tice-2 (US$48) and other of his metal puzzles for sale.