def check():

    H, W = list(map(int, input().split()))

    S = [0]*(H+2)

    S[0] = '.'*(W+2)

    S[H+1] = '.'*(W+2)

    dh = [0,1,0,-1]

    dw = [1,0,-1,0]

    for h in range(1,H+1):

        S[h] = '.' + eval(input()) + '.'

    for h in range(H):

        for w in range(W):

            if S[h][w]=='#':

                for i in range(4):

                    if S[h+dh[i]][w+dw[i]]=='#':

                        break

                else:

                    return 'No'

    return 'Yes'

print((check()))
def check():

    H, W = list(map(int, input().split()))

    S = [0]*(H+2)

    S[0] = '.'*(W+2)

    S[H+1] = '.'*(W+2)

    for h in range(1,H+1):

        S[h] = '.' + eval(input()) + '.'

    

    dh = [0,1,0,-1]

    dw = [1,0,-1,0]

    

    for h in range(1,H+1):

        for w in range(1,W+1):

            if S[h][w]=='.':

                continue

            for i in range(4):

                h0 = h+dh[i]

                w0 = w+dw[i]

                if S[h0][w0]=='#':

                    break

            else:

                return 'No'

    return 'Yes'

    

print((check()))
def check():
    H, W = list(map(int, input().split()))
    S = [0] * (H + 2)
    S[0] = "." * (W + 2)
    S[H + 1] = "." * (W + 2)
    dh = [0, 1, 0, -1]
    dw = [1, 0, -1, 0]
    for h in range(1, H + 1):
        S[h] = "." + eval(input()) + "."
    for h in range(H):
        for w in range(W):
            if S[h][w] == "#":
                for i in range(4):
                    if S[h + dh[i]][w + dw[i]] == "#":
                        break
                else:
                    return "No"
    return "Yes"


print((check()))

def check():
    H, W = list(map(int, input().split()))
    S = [0] * (H + 2)
    S[0] = "." * (W + 2)
    S[H + 1] = "." * (W + 2)
    for h in range(1, H + 1):
        S[h] = "." + eval(input()) + "."
    dh = [0, 1, 0, -1]
    dw = [1, 0, -1, 0]
    for h in range(1, H + 1):
        for w in range(1, W + 1):
            if S[h][w] == ".":
                continue
            for i in range(4):
                h0 = h + dh[i]
                w0 = w + dw[i]
                if S[h0][w0] == "#":
                    break
            else:
                return "No"
    return "Yes"


print((check()))

+    for h in range(1, H + 1): +        S[h] = "." + eval(input()) + "." -        S[h] = "." + eval(input()) + "." -    for h in range(H): -        for w in range(W): -            if S[h][w] == "#": -                for i in range(4): -                    if S[h + dh[i]][w + dw[i]] == "#": -                        break -                else: -                    return "No" +        for w in range(1, W + 1): +            if S[h][w] == ".": +                continue +            for i in range(4): +                h0 = h + dh[i] +                w0 = w + dw[i] +                if S[h0][w0] == "#": +                    break +            else: +                return "No"