function myout(text){console.log(text);}//standard output
function Main(input) {
	input = input.trim();
	//input = input.trim().split(" ");
	input = input.trim().split("\n");
	//input = input.trim().split(" ").map((a)=>Number(a));
	//input = input.trim().split("\n").map((a)=>Number(a));
  var H = parseInt(input[0].split(" ")[0]);
  var W = parseInt(input[0].split(" ")[1]);
  for(var i = 1; i <= H; i++){
    input[i] = input[i].split("");
  }
  input.shift();
  for(var i = 0; i < H; i++){
    for(var j = 0; j < W; j++){
      var check = input[i][j];
      if(check == "#"){
         var u = ".";
        if(i != 0){
           u = input[i - 1][j];
        }
         var l = ".";
        if(j != 0){
           l = input[i][j - 1];
        }
         var r = ".";
        if(j != W - 1){
           r = input[i][j + 1];
           }
         var d = ".";
        if(i != H - 1){
           d = input[i + 1][j];
           }
        
         if(u !== "#" && l !== "#" && r !== "#" && d !== "#"){
            myout("No");
           return;
            }
      }
    }
  }
  myout("Yes");
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
