H,W = map(int,(input().split()))
L = [[] for _ in range(H)]

for i in range(H):
    L[i] = list(input())

for i in range(H):
    for j in range(W):

        if L[i][j] == "#":

            c = 0
            if i-1 >= 0:
                if L[i-1][j] == "#":
                    c += 1
            if i+1 < H-1:
                if L[i+1][j] == "#":
                    c += 1
            if j-1 >= 0:
                if L[i][j-1] == "#":
                    c += 1
            if j+1 < W-1:
                if L[i][j+1] == "#":
                    c += 1

            if c == 0:
                print("No")
                break
    
    else:
        continue
    break
else:
    print("Yes")