What are your opinions on that size of a board. mtbikesman had mentioned it on the main chat board. I had never really thought about it before, but had seen it mentioned on Wikipedia. mtbikesman said it made for some wild games, I can imagine. It would be like playing 18 holes of golf out on the prairie in eastern Colorado, extending through Kansas. I guess you cam make a board with parts of three game boards of the 24x24 3m version. Makes sense, and my next adventure.

*If you intend to make a 36x36 set out of nine 3M panels, you're going to have to drill out the corner hole on several of those panels. A drill press is recommended if you can gain access to one, but a hand drill will do if you make sure the panel is stable and secure before you drill. Avalon Hill sets might have the corner holes of each panel already drilled out. I believe they are the exact same size and use the same hole size as 3M sets. This means one of those three sets could be 3M, and those four panels will go in the corners of the 36x36 grid. Use a straight razor to gently scrape off the superfluous border lines. Don't try to rub the border lines out, because that will push the paint into the slightly porous plastic, and it will look nasty. I used tape to hold the sections together for my version. If you have the paid version of Zillions of Games, you can download a [url=http://www.zillions-of-games.com/cgi-bin/zilligames/submissions.cgi?do=show;id=894]Twixt module[/url] which has a 36x36 option. This module is strictly for playing another human online; the computer play feature does not work for this module. I certainly don't recommend you buy the Zillions registration key just to play Twixt.
Another project you might consider, for the standard size board or any size, is to add [url=https://www.boardgamegeek.com/image/268974/twixt]diagonal guide lines[/url].*[size=12pt]If you intend to make a 36x36 set out of nine 3M panels, you're going to have to drill out the corner hole on several of those panels. A drill press is recommended if you can gain access to one, but a hand drill will do if you make sure the panel is stable and secure before you drill. Avalon Hill sets might have the corner holes of each panel already drilled out. I believe they are the exact same size and use the same hole size as 3M sets. This means one of those three sets could be 3M, and those four panels will go in the corners of the 36x36 grid. Use a straight razor to gently scrape off the superfluous border lines. Don't try to rub the border lines out, because that will push the paint into the slightly porous plastic, and it will look nasty. I used tape to hold the sections together for my version. If you have the paid version of Zillions of Games, you can download a Twixt module http://www.zillions-of-games.com/cgi-bin/zilligames/submissions.cgi?do=show;id=894[url=http://www.zillions-of-games.com/cgi-bin/zilligames/submissions.cgi?do=show;id=894]Twixt module[/url] which has a 36x36 option. This module is strictly for playing another human online; the computer play feature does not work for this module. I certainly don't recommend you buy the Zillions registration key just to play Twixt.
Another project you might consider, for the standard size board or any size, is to add diagonal guide lines https://www.boardgamegeek.com/image/268974/twixt[url=https://www.boardgamegeek.com/image/268974/twixt]diagonal guide lines[/url].[/size]

Hey, thanks for the advice. I haven't got to it yet, soon. I knew about drilling the corner holes, but thanks a million on the advice about the paint (using a razor). I was going to try to rub them off. I won't now.

Another option you might consider is to use white pegboard cut to 36X36.  You will need to find something to work as pegs and links.  I bet you could find something at a hobby center (Hobby Lobby?)  Links could be colored pipe cleaners.  Racing stripe tape would make good border lines and diagonal lines.  For portability, you could create 4 squares to equal the board and use something to act as hinges like the original plastic board game.