H,W = map(int,input().split())

drawMap=[]

i=0
while i<H:
  drawMap.append([])
  tempLine=input()
  
  j=0
  while j<W:
    drawMap[i].append(tempLine[j])
    j=j+1
  i=i+1
  
flag="Yes"

i=0
while i<H:
  j=0
  while j<W:

    #print("ij",i,j)
    if drawMap[i][j]=="#":
      tempFlag=0
      y=max([i-1,0])
      while y<i+2 and y<H:
        x=max([j-1,0])
        while x<j+2 and x<W:
          #print(i,j,y,x)
          if (x+y)%2==1  and drawMap[y][x]=="#":
            #print(i,j,y,x)
            tempFlag=1
          x=x+1
        y=y+1
      if tempFlag==0:
        flag="No"
        #print("No")
      
    j=j+1
  i=i+1

#print(drawMap)
print(flag)