let bitmap = new System.Drawing.Bitmap(fst GUI.BoardSize, snd GUI.BoardSize)
    GUI.gamePicture.Image <- bitmap

    let drawGameBoard () =
        let data = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), Imaging.ImageLockMode.ReadWrite, bitmap.PixelFormat)
        let size = abs(data.Stride) * data.Height
        let buf = Array.create size 0uy
        System.Runtime.InteropServices.Marshal.Copy (data.Scan0, buf, 0, size)
        for cellX in { 0 .. fst GUI.CellCount - 1 } do
            for cellY in { 0 .. snd GUI.CellCount - 1 } do
                let color = if gameBoard.[cellX, cellY] then 0uy else 255uy
                for x in { 0 .. GUI.CellSize - 1 } do
                    for y in { 0 .. GUI.CellSize - 1 } do
                        let r = ((cellY * GUI.CellSize + y) * data.Stride) + (cellX * GUI.CellSize + x) * 4
                        buf.[r] <- color
                        buf.[r+1] <- color
                        buf.[r+2] <- color
                        buf.[r+3] <- 255uy
        System.Runtime.InteropServices.Marshal.Copy (buf, 0, data.Scan0, size)
        bitmap.UnlockBits(data);
        GUI.gamePicture.Invalidate()