H,W=map(int,input().split())
endmap=[list(s for s in input()) for _ in range(H)]
exlarge=[[0]*(W+2)*(H+2)]
ans='Yes'
for i in range(H):
  for j in range(W):
    if endmap[i][j]=='#':
      exlarge[i+1][j+1]=1
 
for k in range(H+2):
  for l in range(W+2):
    if exlarge[k][l]==1: 
        if exlarge[k][l-1]== exlarge[k][l+1]==exlarge[k-1][l]==exlarge[k+1][l]==0:
          ans='No'
 
print(ans)