import java.util.Scanner;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int rt = sc.nextInt();
        while (rt>0) {
            int rn = sc.nextInt();
            for (int i=0;i<2*rn;i++){
                for (int j=0;j<rn;j++){
                    if((i / 2 + j) % 2 != 0){
                        System.out.print("..");
                    } else {
                        System.out.print("##");
                    }
                }
                System.out.println();
            }
            rt--;
        }
    }
}

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4
1
2
3
4