TetraVex is an edge-matching puzzle. The player is presented with a grid (by default, 3x3) and nine square tiles, each with a number on each edge. The objective of the game is to place the tiles in the grid in the proper position as fast as possible. Two tiles can only be placed next to each other if the numbers on adjacent faces match.
A 32-bit Windows version was written in Delphi by Mark Billig 
The original version of TetraVex (for the Windows Entertainment Pack 3) was written (and named) by Scott Ferguson who was also the Development Lead and an architect of the first version of Visual Basic. TetraVex was inspired by "the problem of tiling the plane" as described by Donald Knuth on page 382 of Volume 1: Fundamental Algorithms, the first book in his The Art of Computer Programming series.
In the TetraVex version for Windows, the Microsoft Blibbet logo is displayed if the player solves a 6 by 6 puzzle as seen in the image to the right.
Counting the possible number of TetraVex
On a board there are horizontal and vertical pairs that must match and numbers along the edges that can be chosen arbitrarily. Hence there are choices of 10 digits, i.e. possible boards. Deciding if a TetraVex puzzle has a solution is in general NP-complete.
- "License - README". gnome-games. gnome.org. 2011. Retrieved 2012-10-02.
- "Tetravex Game - Fancy Delphi Application Contest Entry #39". about.com. 2008. Archived from the original on September 5, 2008.
- "The Birth of Visual Basic". Forestmoon.com. Retrieved 2010-05-11.
- "MacMahon squares". Daviddarling.info. 2007-02-01. Retrieved 2010-07-30.
- "TetraVex is NP-complete". Information Processing Letters, Volume 99, Issue 5, Pages 171–174. 15 September 2006.