The first is my Theta (the exact name is 9 Theta) since it has 9 burr pieces plus a cage. Excellently constructed of Maple and Purpleheart, this one has a level 18.104.22.168.2.1.2 solution requiring a total of 29 steps to completely disassemble. Great attention to detail here and yes, I still need Burr Tools to help me re-assemble after taking it apart.
Currently all 48 limited edition copies are sold out. Personally for me it was a nice design exercise and really a "no big deal" kind of interlocking burr. My burr design capabilities are pretty limited and I was surprise Eric chose Theta to produce for his site. But the few comments I have received from purchasers of this puzzle has generally been good.
My second design is a sliding block puzzle called Triple Tango. I was able to design Triple Tango thanks to Goh Pit Khiam who shared with me his sliding block design program which he authored a while back (a software that works similar to Burr Tools, where you can specify the shape and units of the pieces etc).
There is also a freeware programme called the SBP Solver by Pierre-Francois Culand but this program is rather limited in that the shapes for the pieces can only be either squares or rectangles. But for anyone who has never designed a sliding block puzzle, the SBP Solver is good enough to get you going for a start.
To see the many incredible sliding block puzzle designs out there including those by Minoru Abe, Serhiy Grabarchuk, Ed Pegg, Nob Yoshigahara just to name a few, check out Nick Baxter's Sliding Block Puzzle Page.
Again this was a surprise for me as I didn't think Eric would produce a sliding block puzzle like that where the pieces are uncovered. Anyway 46 copies of the Triple Tango were made and they are all also sold out!