H,W = map(int, input().split())
S=[list(map(str,list(input()))) for i in range(H)] 

A = [['.']*(W+2) for i in range(H+2)]
for i in range(1,H+1):
    for j in range(1,W+1):
        A[i][j] = S[i-1][j-1]
        
ans = 'Yes'
for i in range(W+2):
    if(ans == 'No'):
        break
    for j in range(H+2):
         if(A[H][W] == '#'):
            if (A[H-1][W] != '#' and A[H+1][W] != '#' and A[H][W-1] != '#' and A[H][W+1] != '#'):
                ans = 'No'
                break

print(ans)
