<?php

$lines = array_map("trim", file("php://stdin"));
list($height, $width) = explode(" ", array_shift($lines));
$height = intval($height);
$width = intval($width);
$map = array_map("str_split", $lines);
$canDraw = true;
foreach($map as $y => $row) {
  foreach($row as $x => $char) {
    $neighboars = getNeighborsChar($map, $x, $y);
    $notBlackValues = array_filter($neighboars, function($v) {
      return is_null($v) || $v === '.';
    });
    if (count($notBlackValues) === count($neighboars)) {
      $canDraw = false;
      break;
    }
  }

  if (!$canDraw) {
    break;
  }
}

echo $canDraw ? "Yes" : "No";

function getCharOn($map, $x, $y) {
  if (count($map) <= $y || $y < 0) {
    return null;
  }
  
  $row = $map[$y];
  if (count($row) <= $x || $x < 0) {
    return null;
  }

  return $row[$x];
}

function getNeighborsChar($map, $x, $y) {
  return [
    'right' => getCharOn($map, $x + 1, $y),
    'left' => getCharOn($map, $x - 1, $y),
    'up' => getCharOn($map, $x, $y - 1),
    'down' => getCharOn($map, $x, $y + 1)
  ];
}