local h, w = io.read("*n", "*n", "*l")
local str = ""
local t = {}
for i = 1, h do
  str = io.read()
  for j = 1, w do
    t[(i - 1) * w + j] = string.sub(str, j, j) == "#" and true or false
  end
end
local s = h * w
local allok = true
for i = 1, s do
  if(t[i]) then
    local isok = false
    if(w < i) then
      if(t[i - w]) then isok = true end
    end
    if(i <= s - w) then
      if(t[i + w]) then isok = true end
    end
    if(i % w ~= 0) then
      if(t[i + 1]) then isok = true end
    end
    if(i % w ~= 1) then
      if(t[i - 1]) then isok = true end
    end
    if(not isok) then allok = false break end
  end
end
print(allok and "Yes" or "No")
