Java

Tissellator is a program for creating M.C. Escher tessellations, circle and spiral tessellations, and even gif animations. Tissellator can be found at https://www.tissellator.com .

The H6X9H program for generating H6X9H figures can be found at http://www.tistis.nl/H6X9H .

The BbnOrganiser tool for bridge bidding systems can be found at http://www.tistis.nl/bbn .

The Tralihs game can be found at http://www.tistis.nl/tralihs .

The PBN Verifier and the PBN Viewer can be found at http://www.tistis.nl/pbn at PBN software.

My simple Java tools :
chext.jar chext.zip Change file extensions
diff.jar diff.zip Indicate differences between files in 2 directories
eol.jar eol.zip Convert/remove end-of-line markers
  hexer.jar   hexer.zip Create hex dump for c-like programs
  jh.jar   jh.zip Join html files to one file, also recursively from subdirectories
  join.jar   join.zip Join files to one file, also recursively from subdirectories
split.jar split.zip Split and merge files for transport on floppies
  tab.jar   tab.zip Add and remove tabs