function Main(s) {
	s = s.split("\n");
  s[0] = s[0].split(" ").map(a => +a);
  const h = s[0][0];
  const w = s[0][1];
  var ans = "Yes";
  for(var i = 1; i <= h; i++)
  for(var j = 0; j < w; j++){
    if(s[i][j] === ".")continue;
    if(i !== 1) if(s[i-1][j] === "#")continue;
    if(i !== h) if(s[i+1][j] === "#")continue;
    if(j !== 0) if(s[i][j-1] === "#")continue;
    if(j !== w - 1) if(s[i][j+1] === "#")continue;
    ans = "No";
  }
  console.log(ans);
}

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