#include <iostream>
using namespace std;
 
void printGrid(int l, int c, int h, int w){
	string grid = "";
	int x = c * (w + 1) + 1, y = l * (h + 1) + 1;
	for (unsigned i = 0; i < y; i++){
		for (unsigned j = 0; j < x; j++){
			if (i % (h+1) == 0 || j % (w+1) == 0) grid += "*";
			else grid += ".";
		}
		grid += "\n";
	}
	cout << grid;
 
}
 
int main() {
	int t, l, c, h, w;
	cin >> t;
 
	for (unsigned i = 0; i < t; i++){
		cin >> l >> c >>h >> w;
 
		printGrid(l, c, h, w);
 
	}
 
	return 0;
}

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