process.stdin.resume();
process.stdin.setEncoding('utf8');

var g_input = '';
process.stdin.on('data', function(chunk) {
    g_input += chunk;
});

process.stdin.on('end', function() {
    Main(g_input.split(/\r?\n/));
});

function Main(input) {

    var hw = input[0].split(' ');
    var h = parseInt(hw[0], 10);
    var w = parseInt(hw[1], 10);

    var i = 0;
    var grid = [];
    for (i = 0; i < h; i++) {
        var line = input[1 + i].split('');
        grid[i] = line;
    }

    var ans = true;
    var j = 0;
    for (i = 0; i < h; i++) {
        for (j = 0; j < w; j++) {
            if (grid[i][j] === '#') {
                if ((i === 0 || grid[i - 1][j] === '.') &&
                    (i === h - 1 || grid[i + 1][j] === '.') &&
                    (j === 0 || grid[i][j - 1] === '.') &&
                    (j === w - 1 || grid[i][j + 1] === '.')) {

                    ans = false;
                    break;
                }
            }
        }

        if (!ans) {
            break;
        }
    }

    if (ans) {
        console.log('Yes');
    }
    else {
        console.log('No');
    }

    return 0;
}
