Over the Easter break, we visited Honister Slate Mine in Cumbria. They sold lots of nice slate products, but they were all really expensive.

Then we saw the off-cuts box.

Several of the things they sold had holes drilled in them to take tea-lights, and they sold the holes as well! They must be useful for something ...

So, as my pocket became a couple of pounds lighter, my arms became a couple of pounds heavier.*

Later in the day, after a (very interesting) tour of the mine, the guide let us take our pick of a centuries-old spoil-heap. Guess who grabbed the biggest piece he could lift?

An idea quickly formed - make a board game out of slate, so you can leave it in the garden.

_{*See the clever linguistics you miss by not being British?}

Step 1: Ideas

OK, we're making a board game, but which one?

It turned out that the slab would carry a 5x5 grid of pieces quite comfortably, so I decided to find a game that could be played on a 5x5 grid.

I thought about Quick Chess, Hyle, square solitaire and three, six or nine-men's morris, but I eventually settled on Seega (also known as siga, Egyptian siga, or woodsense or Fidchell - versions of the game seem to have sprung up all over the world). Apparently it is still played in Eygpt and Somalia.

The most playable version came from GameCabinet.

Step 2: Pieces

Seega is played with 12 pieces each.

From the thirty offcuts, I selected the 24 with the flattest bases and least-lumpy tops.

Had I been using wood, I would have painted or stained half the pieces. Instead, I used my rotary tool to engrave a circle in the top of one of the spare pieces. The best bit for the job turned out to be the one that looks like a dental tool (deburring tool?), and the best size for the circle turned out to be the same size as a 10p piece.

So, using a 10p piece and a yellow pencil-crayon, I drew circles on half the pieces and then went over the circle with the rotary tool. The other twelve pieces I left plain.

I was using the flexible extension piece, and it tended to get rather warm after three or four circles, so the whole engraving process took some time, mainly because I had to stop and wait for things to cool down every so often.

Step 3: Board

The pieces were 3.5cm across, which meant that a 5x5 board would be 20cm x 20cm.

I drew a grid out in Corel, and added diagonals "just in case" - I had not yet worked out how to transfer the board design to the slate.

Transferring the design proved to be rather simple: I cut out the board, marked the corners and ends of lines on the slate in yellow pencil, then used a ruler to join the dots.

I then used the dental tool again to draw in the grid lines and the central square's X (see how to play).

As I did all this engraving, I found that I had to lay the rotary tool down at a lower and lower angle to get a decent cut. At first, I thought I was just getting used to carving long lines, then I realised that I was wearing out my tool. Since Honister slate is supposed to last upwards of 300 years as a roofing and building material (compared to "only" 150 years for Welsh slate), I guess it's not surprising that I wore out the bit. I guess the professionals use diamond tips or similar.

Step 4: Playing the Game.

Seega is a simple game to play, with a lot of the feel of games like draughts and Othello.

Players take it in turn to place two pieces on the board at a time, anywhere on the board.

Once all the pieces are on the board, players continue to take turns, moving pieces orthogonally (like the rooks in chess) to try and capture.

Capture is achieved by trapping the opponent's pieces between two of your own pieces (like Othello). Captured pieces are removed from the board.

Pieces are immune from capture if they are on the central X square.

Play continues until one player is reduced to one (or no) pieces, or until both players have built an impenetrable wall, in which case the game is a draw.

Equally-matched players will get a lot of draws, so once you are comfortable with the game, you can start adding any of the variant rules played around the world;