H,W = map(int,input().split())
L = []
for i in range(H) :
    L.append(list(input()))
flag = 0
if H == 1 :
    if W == 1 :
        if L[H][W] != "#" :
            flag = 1
    else :
        if L[i][j] == "#" :
            if j == 0 :
                if L[i][j+1] != "#" :
                    flag = 1
            elif j == W-1 :
                if L[i][j-1] != "#" :
                    flag = 1
            else :
                if (L[i][j+1] != "#") and (L[i][j-1] != "#") :
                    flag = 1
else :
    for i in range(H) :
        for j in range(W) :
            if L[i][j] == "#" :
                if j == 0 :
                    if i == 0 :
                        if (L[i+1][j] != "#") and (L[i][j+1] != "#") :
                            flag = 1
                    elif i == (W-1) :
                        if (L[i-1][j] != "#") and (L[i][j+1] != "#") :
                            flag = 1
                    else :
                        if (L[i-1][j] != "#") and (L[i][j+1] != "#") and (L[i+1][j] != "#") :
                            flag = 1
                elif j == (H-1) :
                    if i == 0 :
                        if (L[i+1][j] != "#") and (L[i][j-1] != "#") :
                            flag = 1
                    elif i == (W-1) :
                        if (L[i-1][j] != "#") and (L[i][j-1] != "#") :
                            flag = 1
                    else :
                        if (L[i-1][j] != "#") and (L[i][j-1] != "#") and (L[i+1][j] != "#") :
                            flag = 1
                else :
                    if i == 0 :
                        if (L[i+1][j] != "#") and (L[i][j+1] != "#") and (L[i][j-1] != "#") :
                            flag = 1
                    elif i == (W-1) :
                        if (L[i-1][j] != "#") and (L[i][j+1] != "#") and (L[i][j-1] != "#") :
                            flag = 1
                    else :
                        if (L[i-1][j] != "#") and (L[i][j+1] != "#") and (L[i+1][j] != "#") and (L[i][j-1] != "#") :
                            flag = 1
            if flag == 1 :
                break
        if flag == 1 :
            break
if flag == 0 :
    print("Yes")
else :
    print("No")

