Create a custom board with missing tiles

Hi all,

My goal is to create a custom board. The problem with the board is that it contains missing tiles. It's a rectangle missing some tiles. Here is the final result I am expecting. (stars represent empty tiles and 1 represent tiles)

**11111*

11111111

11111111

11111*

I am now drawing a full board 8*4 but I am unable to miss the tiles with stars any idea how to do so? Here is my piece of code.

     Vector3 widthLine = Vector3.right * 4;
     Vector3 heightLine = Vector3.forward * 8;

     for (int i=0; i <= 8; i++){
         for (int j=0; j<=4; j++){
             Vector3 start = Vector3.forward * i ;
             Debug.DrawLine(start, start + widthLine);
             start = Vector3.right * j;
             Debug.DrawLine(start, start + heightLine);
         }
     }

Thanks in advance.

P.S: Sorry I am pretty new to coding.