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 endmap[i][j]==1: 
        if endmap[i][j-1]!=1 or endmap[i][j+1]!=1 or endmap[i-1][j]!=1 or endmap[i+1][j]!=1:
          ans='No'

print(ans)
    
        