H,W=map(int,input().split())
S=[input() for i in range(H)]
ans="Yes"
for i in range(W):
    for j in range(H):
        Tonari=[]
        if i>0:
            Tonari.append(S[i-1][j])
        if i<W-1:
            Tonari.append(S[i+1][j])
        if j>0:
            Tonari.append(S[i][j-1])
        if j<H-1:
            Tonari.append(S[i][j+1])
        if S[i][j]=='#' and all([t=='.' for t in Tonari]):
            ans="No"
print(ans)