h, w = map(int, input().split())
S = [input() for _ in range(h)]

ul = [[0] * w for _ in range(h)]
ur = [[0] * w for _ in range(h)]
dl = [[0] * w for _ in range(h)]
dr = [[0] * w for _ in range(h)]

for i in range(h):
    for j in range(w):
        if S[i][j] == ".":
            continue
        if i == 0:
            ul[i][j] = 1
            ur[i][j] = 1
            continue
        ul[i][j] = 1
        ur[i][j] = 1
        if j != 0:
            ul[i][j] = ul[i - 1][j - 1] + 1
        if j != w - 1:
            ur[i][j] = ur[i - 1][j + 1] + 1

for i in range(h - 1, -1, -1):
    for j in range(w):
        if S[i][j] == ".":
            continue
        if i == h - 1:
            dl[i][j] = 1
            dr[i][j] = 1
            continue
        dl[i][j] = 1
        dr[i][j] = 1
        if j != 0:
            dl[i][j] = dl[i + 1][j - 1] + 1
        if j != w - 1:
            dr[i][j] = dr[i + 1][j + 1] + 1


ul_imos = [[0] * (w + 1) for _ in range(h + 1)]
ur_imos = [[0] * (w + 1) for _ in range(h + 1)]
for i in range(h):
    for j in range(w):
        mi = min(ul[i][j], ur[i][j], dl[i][j], dr[i][j])
        if mi <= 1:
            continue
        mi -= 1
        ul_imos[i - mi][j + mi] += 1
        if j - mi - 1 >= 0:
            ul_imos[i + mi + 1][j - mi - 1] -= 1
        ur_imos[i - mi][j - mi] += 1
        ur_imos[i + mi + 1][j + mi + 1] -= 1


for i in range(1, h + 1):
    for j in range(w + 1):
        if j != w:
            ul_imos[i][j] += ul_imos[i - 1][j + 1]
        if j != 0:
            ur_imos[i][j] += ur_imos[i - 1][j - 1]


ok = True
for i in range(h):
    for j in range(w):
        if S[i][j] == "#" and ul_imos[i][j] == 0 and ur_imos[i][j] == 0:
            ok = False
            break
    if not ok:
        break

if ok:
    print("Yes")
else:
    print("No")