h,w = map(int,input().split())

ls = [list(input()) for i in range(h)]

t=False

for i in range(h):
    for j in range(w):
        if (ls[i][j]=='#'):
            for x in range(-1,2):
                for y in range(-1,2):
                    if (0<=i+x<h and 0<=j+y<w):
                        if not((x==1 and y==1) or (x==1 and y==-1) or (x==-1 and y==1) or (x==-1 and y==-1)or(x==0 and y==0)):
                      	  if(ls[i+x][j+y]=='#'):
                              t=True
                              continue
                      	  else:
                              break
                        else:
                          continue
                    else:
                      continue
        else:
          continue      
if(t):
    print('Yes')
else:
    print('No')
