import sys

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

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

ans = True
flag = False

for i in range(h):
    for j in range(w):
        if s[i][j] == '#':
            if i == 0:
                if(s[i][j-1] == '.' and s[i+1][j] == '.' and s[i][j+1] == '.'):
                    ans = False
                    break

            elif j == 0:
                if(s[i-1][j] == '.' and s[i+1][j] == '.' and s[i][j+1] == '.'):
                    ans = False
                    break
            elif i == h-1:
                if(s[i-1][j] == '.' and s[i][j-1] == '.' and s[i][j+1] == '.'):
                    ans = False
                    break
            elif j == w-1:
                if(s[i-1][j] == '.' and s[i][j-1] == '.' and s[i+1][j] == '.'):
                    ans = False
                    break
            else:
                if(s[i-1][j] == '.' and s[i][j-1] == '.' and s[i+1][j] == '.' and s[i][j+1] == '.'):
                    ans = False
                    break

    if not(ans):
        break

if ans:
    print('Yes')
else:
    print('No')
