#include <stdio.h>
#include <string.h>
#include <assert.h>

#include <queue>
#include <algorithm>

#define LOG(FMT...) fprintf(stderr, FMT)

#define eb emplace_back
#define em emplace

using namespace std;

typedef long long LL;
constexpr int N = 1024;
constexpr int rem[4] = {3, 1, 2, 0};

char gr[N][N];
int a[N][N];

int main() {
	int n = 1020, m = 1020;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			gr[i + 1][j + 1] = ".#"[(j & 3) != rem[i & 3]];
			a[i + 1][j + 1] = (gr[i + 1][j + 1] == '#') + a[i + 1][j] + a[i][j + 1] - a[i][j];
		}
	}
	int task;
	for (scanf("%d", &task); task--; ) {
		scanf("%d%d", &n, &m);
		if (n < 4) {
			printf("%d\n", n * (m - m / 4));
			for (int i = 0; i < n; ++i) {
				for (int j = 0; j < m; ++j) {
					putchar(".#"[(j & 3) < 3]);
				}
				puts("");
			}
		} else if (m < 4) {
			printf("%d\n", m * (n - n / 4));
			for (int i = 0; i < n; ++i) {
				for (int j = 0; j < m; ++j) {
					putchar(".#"[(i & 3) < 3]);
				}
				puts("");
			}
		} else {
			int res = 0, rx = -1, ry = -1;
			for (int x = 0; x < 4; ++x) {
				for (int y = 0; y < 4; ++y) {
					int v = a[x + n][y + m] - a[x + n][y] - a[x][y + m] + a[x][y];
					if (v <= res) {
						continue;
					}
					res = v, rx = x, ry = y;
				}
			}
			printf("%d\n", res);
			// LOG("%d\n", min(n * (m - m / 4), m * (n - n / 4)));
			// LOG("+(%d, %d)\n", rx, ry);
			for (int i = 1; i <= n; ++i) {
				for (int j = 1; j <= m; ++j) {
					putchar(gr[rx + i][ry + j]);
				}
				puts("");
			}
		}
	}
	return 0;
}