from sys import stdin
input = lambda: stdin.buffer.readline().decode().strip()


def solve(ans):
    ct = 0
    for x in ans:
        ct += x.count('#')
    return ct >> 1


for _ in range(int(input())):
    n = int(input())

    if n == 4:
        ans = ['##.#', '...#', '#...', '#.##']
        print('\n'.join(ans))

    else:
        x, y = 0, 0
        while 2*(x+1) - 1 <= n and n - (2*(x+1) - 1) != 1:
            x += 1
        
        while 3*(y+1) - 1 <= n and n - (3*(y+1) - 1) != 1:
            y += 1

        ans = [['.' for _ in range(n)] for _ in range(n)]
        dx, dy = n-(2*x-1), n-(3*y-1)

        for i in range(dx, n, 2):
            for j in range(dy, n, 3):
                ans[i][j] = '#'
                ans[i][j+1] = '#'
        

        if dx == 3:
            for j in range(n-1, max(1, dy-1), -2):
                ans[0][j] = ans[1][j] = '#'

        if dy >= 2:
            for i in range(n-1, max(1, dx-1), -3):
                # print(n, i, dx)
                ans[i][0] = ans[i-1][0] = '#'
                if dy == 4:
                    ans[i][2] = ans[i-1][2] = '#'

        if n > 3:
            if '#' not in ans[0][:3] and '#' not in ans[1][:3]:
                ans[0][0] = ans[0][1] = '#'

        
        x, y = 0, 0
        while 2*(x+1) - 1 <= n:
            x += 1
        
        while 3*(y+1) - 1 <= n and n - (3*(y+1) - 1) != 1:
            y += 1

        ans2 = [['.' for _ in range(n)] for _ in range(n)]
        dx, dy = n-(2*x-1), n-(3*y-1)

        for i in range(dx, n, 2):
            for j in range(dy, n, 3):
                ans2[i][j] = '#'
                ans2[i][j+1] = '#'
        

        if dx == 3:
            for j in range(n-1, max(1, dy-1), -2):
                ans2[0][j] = ans2[1][j] = '#'

        if dy >= 2:
            for i in range(n-1, max(1, dx-1), -3):
                # print(n, i, dx)
                ans2[i][0] = ans2[i-1][0] = '#'
                if dy == 4:
                    ans2[i][2] = ans2[i-1][2] = '#'

        if n > 3:
            if '#' not in ans2[0][:3] and '#' not in ans2[1][:3]:
                ans2[0][0] = ans2[0][1] = '#'

        if solve(ans2) > solve(ans):
            ans = ans2[:]

        if n > 5:
            if '#' not in ans[1][:3] and '#' not in ans[2][:3] and '#' not in ans[3][:3]:
                ans[2][0] = ans[2][1] = '#'

            if ans[0][2] == ans[0][3] == ans[0][4] == ans[1][2] == ans[1][3] == ans[1][4] == '.':
                ans[0][3] = ans[1][3] = '#'

        for x in ans:
            print(''.join(x))