import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;


void main() {
    int h, w; scan(h, w);

    if (h == 1 && w == 1) {
        writeln("No");
        return;
    }

    auto ban = new char[][](h, w);
    iota(h).each!(i => ban[i] = readln.chomp.dup);

    int[] di = [0, 1, 0, -1];
    int[] dj = [1, 0, -1, 0];

    foreach (i ; 0 .. h) {
        foreach (j ; 0 .. w) {
            if (ban[i][j] == '.') continue;
            int cnt;

            foreach (k ; 0 .. 4) {
                int ni = i + di[k];
                int nj = j + dj[k];
                if (ni < 0 || ni >= h) continue;
                if (nj < 0 || nj >= w) continue;
                if (ban[ni][nj] == '#') cnt++;
            }

            if (cnt == 0) {
                debug {
                    writefln("(%d, %d)", i, j);
                }
                writeln("No");
                return;
            }
        }
    }

    writeln("Yes");
}




void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}



void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
