SZ stands for Serguey Zefirov. I am a 31-year old Tcl and other languages hacker from Russia. Right now it is my job to hack Tcl, around Tcl and with Tcl. Most of my recent programs are all done in Tcl. Russian-enabled readers can go to [http://lazyone.narod.ru] for some more information. My current employer is [http://www.psit.ru], also in Russian. In short - credit and debit card processing software, ATM and POS software. I, for long time, was fascinated with [Functional Programming] languages, especially Haskell (see [Playing Haskell]) (actually, I found Tcl/Tk trying to start up FranTk - Haskell declarative GUI library on top of Tk). So I decided to reproduce its useful feature, called [Algebraic Types].