def checkA(x):
    i,j = x[0],x[1]
    if A[i][j]=="#":
        if A[i][j+1]=="." and A[i-1][j]=="." and A[i][j-1]=="." and A[i+1][j]==".":
            return 1
        else:
            return 0
    else:
        return 0      
H,W = map(int,input().split())
A = [["." for _ in range(W+2)]]
for i in range(H):
    row = list(input())
    row.insert(0,".")
    row.append(".")
    A.append(row)
A.append(["." for _ in range(W+2)])
ind = 0
for i in range(1,H+1):
    for j in range(1,W+1):
        if A[i][j]=="#":
            ind = 1
            break
    if ind==1:break
if ind==0:
    ind = 1
else:
    ind = 0
    for i in range(1,H+1):
        for j in range(1,W+1):
            ind = checkA([i,j])
            if ind==1:
                break
if ind==1:
    print("No")
else:
    print("Yes")