h, w = map(int, input().split())

s = [input() for i in range(h)]

for i in range(1,h-1):
    for j in range(1, w-1):
        if s[i][j]=="#" and s[i+1][j]=="." and s[i][j+1]=="." and s[i-1][j]=="." and s[i][j-1]==".":
            print("No")
            exit()

for j in range(1,w-1):
    if s[0][j] == "#" and s[1][j] == "." and s[0][j + 1] == "." and s[0][j - 1] == ".":
        print("No")
        exit()
    if s[h-1][j] == "#" and s[h-2][j] == "." and s[h-1][j + 1] == "." and s[h-1][j - 1] == ".":
        print("No")
        exit()


for i in range(1,h-1):
    if s[i][0] == "#" and s[i + 1][0] == "." and s[i][1] == "." and s[i - 1][0] == ".":
        print("No")
        exit()
    if s[i][w-1] == "#" and s[i + 1][w-1] == "." and s[i][w-2] == "." and s[i - 1][w-1] == ".":
        print("No")
        exit()

if s[0][0]=="#" and s[1][0]=="." and s[0][1]==".":
    print("No")
    exit()

if s[h-1][0]=="#" and s[h-1][1]=="." and s[h-2][0]==".":
    print("No")
    exit()

if s[0][w-1]=="#" and s[1][w-1]=="." and s[0][w-2]==".":
    print("No")
    exit()

if s[h-1][w-1]=="#" and s[h-1][w-2]=="." and s[h-2][s-1]==".":
    print("No")
    exit()

print("Yes")