The Cast Cake is the brainchild of IPP award-winning designer Bram Cohen, who also designed the Cast Rattle and the Cast Galaxy, the latter one of my personal Cast favourites.
The Cake, well, it's round and looks like a cake with a slice of it eaten. And it measures 4cm in diameter. It looks to me to be made of stonewashed brass or copper as it has a pretty good heft to it. Construction fit and finish on my copy is very good and everything fits and moves nicely without any experiencing of jamming.
The Cake consists of a 3/4 hollowed out circular "cage" and inside resides 3 rotating 3/4 discs sandwiched against one another. The object is to remove the 3 discs from the cage.
It's rated 4 out of 6 stars meaning that its more than moderately difficult but I think it deserves 5 stars because it is way harder than it looks or what I had expected. At first I thought one of the discs could "spiral" its way sideways out like a circular burr, so I tried solving it that way, but apparently not. It took me a good half and hour of manipulating and rolling the 3 discs inside and trying to feel for an "opening" of sorts before suddenly I felt something give and I was able to pull the discs out. I am not sure what I had done but it worked. As I was re-assembling the puzzle, I took time to experiment and was able to discover a technique to it. Thereafter I was able to repeat solving the Cake a majority of the time. Very challenging at first but once you understand what needs to be done (and I am not going to say anymore here to spoil other people's fun), its a matter of practice to get it right.
If anyone needs help, please PM me (I will have to draw a diagram to show you as it is impossible to explain in words).
Currently only available in Japan but should hit retail stores in other countries and available from the usual online sellers in the weeks to come.