interface "AP WIN" a freeware, for using with Windows XP or Windows 7 has since been developed by Paul H. Wiereyn. Using this one can create diagrams and use Popeye for solving problems directly from the diagram. Chloe and Winchloe Chloe (DOS) and Winchloe (proprietary software) are solving programs written by Christian Poisson. Winchloe not only supports classical problems — direct mates, helpmates and selfmates — but also many fairy pieces and conditions with different sized chessboards (up to 250 by 250 squares). It comes with a collection of more than 300,000 problems that can be updated via the Internet. Christian Poisson also maintains the Web site Problemesis. Natch and iNatch Natch and iNatch are freeware programs written by Pascal Wassong for DOS and Linux. Natch solves retrograde analysis problems by constructing a "proof game" - the shortest possible game leading to a certain position. Natch is a command line utility, but there is a Java based graphical interface. iNatch also provides moves with fairy conditions: monochrome chess, Einstein chess, vertical cylinder. Problemist(e) Problemist is a shareware program written by Matthieu Leschamelle for Windows and Windows Mobile. Problemist solves direct mates, helpmates, selfmates and reflexmates. It can rotate positions, print diagrams and much more. With Problemist come two TrueType chess fonts, and from its web page one can download more than 100,000 problems. Problemist is the first chess problems exchange format. Jacobi Jacobi is a program to solve fairy chess proof game problems by François Labelle. It is written in JavaScript and run from browser . In 2003, Labelle already developed chess-related programs and published computer-generated chess problems . Chest Chest was created by Heiner Marxen in 1999. It is written in C, and distributed as source code . It solves direct mates, self mates, and help mates (as well as stalemates for self- and help mates). A UCI adapter (written by Franz Huber) is also available, allowing Chest to be used as solving engine in any UCI-capable chess GUI. Databases Chess Problem Database Server Chess Problem Database Server is online database of all types of chess problems, maintained by Gerd Wilts, hosted by Die Schwalbe. Database incorporated John Niemann collection and the work of a lot of contributors. Database has 428,703 problems (as of November 2019). Problems are represented graphically with solutions and commentary. Other LaTeX Diagram Style Diagram is a style file for LaTeX for typesetting chess diagrams.