function Main(s) {
  var s = s.split("\n");
  var h = s[0].split(" ")[0]*1, w = s[0].split(" ")[1]*1;
  var s = s.slice(1, h + 1);
  var k = [0, -1, 1, 0];
  var l = [-1, 0, 0, 1];
  var head = ["_".repeat(w + 2)];
  var tail = ["_".repeat(w + 2)];
  for(var i = 0; i < h; i++) s[i] = "_" + s[i] + "_";
  var x = head.concat(s).concat(tail);
  var ans = "Yes";
  for(var i = 1; i < h + 1; i++) {
    for(var j = 1; j < w + 1; j++) {
      if (x[i][j] === "#") {
        var cnt = 0;
        for (var m = 0; m < 4; m++) {
          if (x[i + k[m]][j + l[m]] === ".") cnt++;
        }
        if (cnt === 4) {
          ans = "No";
          break;
        }
      }
    }
  }
  console.log(ans);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));