from sys import stdin


if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    H, W = list(map(int,_in[0].split(' ')))  # type:list(int)
    s_arr = []
    for i in range(H):
        _ = [_ for _ in _in[i+1]]   # type:list(str)
        s_arr.append(_)
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    TF = 'Yes'
    for i in range(H):
        if i!=0 and i!=H-1 and TF == 'Yes':
            for j in range(W):
                if j!=0 and j!=W-1 and s_arr[i][j] == '#':
                    adjacent = []
                    if i>1:
                        if s_arr[i-1][j] == '#':
                            continue
                    if i<H-1: 
                        if s_arr[i+1][j] == '#':
                            continue
                    if j>1:   
                        if s_arr[i][j-1] == '#':
                            continue
                    if j<W-1: 
                        if s_arr[i][j+1] == '#':
                            continue
                    TF = 'No'
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(TF)
