import core.bitop, std.algorithm, std.ascii, std.bigint, std.conv,
    std.functional, std.math, std.numeric, std.range, std.stdio, std.string,
    std.random, std.typecons, std.container;

ulong MAX = 100_100, MOD = 1_000_000_007, INF = 1_000_000_000_000;
alias sread = () => readln.chomp();
alias lread(T = long) = () => readln.chomp.to!(T);
alias aryread(T = long) = () => readln.split.to!(T[]);
alias Pair = Tuple!(long, "a", long, "b");
alias PQueue(T, alias less = "a<b") = BinaryHeap!(Array!T, less);

void main()
{
    long h, w;
    scan(h, w);
    auto wall = new string[](h);
    foreach (ref e; wall)
    {
        e = sread();
    }
    // wall.writeln();
    bool ok = true;
    foreach (i; iota(h))
    {
        foreach (j; iota(w))
        {
            if (wall[i][j] == '#')
            {
                ok &= canpaint(wall, i, j);
            }
        }
    }
    if (ok)
        writeln("Yes");
    else
        writeln("No");
}

bool canpaint(ref string[] wall, long i, long j)
{
    bool ret;
    // i.write(" "), j.writeln();
    if (i - 1 >= 0)
        ret |= (wall[i - 1][j] == '#');
    if (i + 1 < wall.length)
        ret |= (wall[i + 1][j] == '#');
    if (j - 1 >= 0)
        ret |= (wall[i][j - 1] == '#');
    if (j + 1 < wall[i].length)
        ret |= (wall[i][j + 1] == '#');

    return ret;
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}
