A story: almost 20 years ago I bought a Burr Set of puzzles from Interlocking Puzzles. The set consisted of 30 to 40 pieces and made 314 6-piece different burr puzzles. It cost $150. I was hesitant because I didn't really understand what a burr puzzle was. When I got it, I worked my way through all 314 puzzles. Took about a month.
The Zobrist Cube comes from Al Zobrist. I saw an advertisement for it in Discover Magazine.
Al Zobrist is the brain behind this monster set. At first glance, the Zobrist Cube looks like an ordinary Soma Cube: assemble the pieces to form a 3x3 cube. However, The Zobrist Cube should be renamed as The Zobrist Cube Set because it comes with 33 pieces - most are unique, some are duplicates.
Each pieces has an embossed letter on it. The Zobrist Cube Set comes with a manual that describes over 20 THOUSAND cube combinations. Fortunately, these are grouped into easy & hard levels.
At the top of the hard levels is a great quote from Stewart Coffin who describes these harder puzzles as '30-minute' puzzles.
Having done a bunch of Soma Cube variations over the years, I instantly headed to the hard ones. The first one I did in 10 minutes. The next one - I gave up after 30 minutes. I skipped to somewhere in the middle and solved the next 3 in about 5 minutes each. I may have been lucky.
Al has turned this puzzle set into a game: 2 people square off, and select 2 random puzzles (with different pieces of course) and see who solves their first.
$35: perfect gift for a kid, adult, a graduation present and for yourself.