"use strict";
function Main(input) {
    let cin = new Inputer(input);
    let H = cin.getInt(), W = cin.getInt();
    let S = new Array(H);
    for (let n = 0; n < H; n++) {
        S[n] = cin.getStr().substr(0, W).split('').map(v => v == '#' ? 1 : 0);
    }
    let ans = true;
    for (let h = 0; h < H; h++) {
        for (let w = 0; w < H; w++) {
            if (S[h][w]) {
                if ((w >= 1 && S[h][w - 1] != 1) && (w < W - 1 && S[h][w + 1] != 1)) {
                    if (h >= 1 && S[h - 1][w] != 1)
                        ans = false;
                    if (h < H - 1 && S[h + 1][w] != 1)
                        ans = false;
                }
            }
            if (!ans) {
                console.log('No');
                return;
            }
        }
    }
    console.log('Yes');
}
class Inputer{constructor(t){if(typeof t=='undefined')throw new Error('引数（stdin）を省略できません！');this.cnt=0,this.items=t.split(/\n|\s/)}getInt(){return this.items[this.cnt++]-0}getIntArray(t){if(typeof t=='undefined')throw new Error('引数（1以上）を省略できません！');let r=new Array(t);for(let e=0;e<t;e++)r[e]=this.getInt();return r}getStr(){return this.items[this.cnt++]}getStrArray(t){if(typeof t=='undefined')throw new Error('引数（1以上）を省略できません！');let r=new Array(t);for(let e=0;e<t;e++)r[e]=this.getStr();return r}}
if (typeof window == "undefined") Main(require("fs").readFileSync("/dev/stdin", "utf8"));