max = 300;
max_log2 = max.toString(2).length - 1;

series = [1, 2];
col = ['#', '#.'];
j = 2;
str = '#.';
for (i = 2; i <= max_log2; i++) {
	series.push(j *= 2);
	col.push(str = str + str);
}
series.push(series[series.length-1] * 2);

function get_column(w) {
	var i, res;
	res = "";
	for (i = 1; i < series.length; i++) {
		if (w < series[i]) break;
		if (w % series[i+1] >= series[i])
			res = res + col[i];
	}
	if (w % 2 === 1) res = res + '#';
	return res;
}

line = require('fs').readFileSync('/dev/stdin', 'ascii').split('\n');
for (i in line) {
	if (line[i] === '0 0') break;
	hw = line[i].split(' ').map(Number);
	even = get_column(hw[1]);
	odd = even.slice(1) + ((hw[1] % 2 === 0) ? '#' : '.');
	for (j = 0; j < hw[0]; j++) {
		if (j % 2 === 0) console.log(even);
		else console.log(odd);
	}
	console.log("");
}