H, W = input().split(" ")
H = int(H)
W = int(W)

s = []
for i in range(W):
    s.append([1 if num=="#" else 0 for num in list(input())])

decision = True

for i in range(W):
    for j in range(H):
        if s[i][j] == 1:
            if i == 0:
                if j == 0:
                    if s[i+1][j]==0 and s[i][j+1]==0:
                        decision=False
                        break
                elif j == H-1:
                    if  s[i][j-1]==0 and s[i+1][j]==0:
                        decision=False
                        break
                else:
                    if  s[i][j-1]==0 and s[i+1][j]==0 and s[i][j+1]==0:
                        decision=False
                        break
            elif j == 0:
                if i == W-1:
                    if s[i-1][j]==0 and s[i][j+1]==0:
                        decision=False
                        break
                else:
                    if s[i-1][j]==0 and s[i+1][j]==0 and s[i][j+1]==0:
                        decision=False
                        break
            elif i == W-1:
                if j == H-1:
                    if s[i-1][j]==0 and s[i][j-1]==0:
                        decision=False
                        break
                else:
                    if s[i-1][j]==0 and s[i][j-1]==0 and s[i][j+1]==0:
                        decision=False
                        break
            elif j == H-1:
                if s[i-1][j]==0 and s[i][j-1]==0 and s[i+1][j]==0:
                    decision=False
                    break
            else:
                if s[i-1][j]==0 and s[i][j-1]==0 and s[i+1][j]==0 and s[i][j+1]==0:
                    decision=False
                    break

if decision == True:
    print("Yes")
else:
    print("No")
