'use strict'

function main(input) {
  const inputList = input.split('\n');
  const dimenstion = inputList[0].split(' ')
  const h = Number(dimenstion[0])
  const w = Number(dimenstion[1])
  const columns = inputList.slice(1)
  const s = columns.map(column => column.split(''))

  const result = checkAdjacentSquares(s, h, w)
  if (result) {
    console.log('Yes')
  } else {
    console.log('No')
  }

}

function checkAdjacentSquares(array, h, w) {
  for (let i=0; i<h; i++) {
    for (let j=0; j<w; j++) {
      if (array[i][j] === '#') {
        if (!canPaint(array, i, j)) {
          return false
        }
      } 
    }
  }

  return true
}

function canPaint(array, i, j) {
  if (i-1>=0 && array[i-1][j] === '#')             return true 
  if (i+1<array.length && array[i+1][j] === '#')   return true
  if (j-1>=0 && array[i][j-1] === '#')             return true 
  if (j+1<array[i].length && array[i][j+1] === '#')return true
  return false
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));