inp = require('fs').readFileSync('/dev/stdin', 'utf8').split('\n')
l = inp.shift().split(' ')
H = l[0] * 1
W = l[1] * 1 
for (i=0; i<H; i++) {
  b = false
  for (j=0; j<W; j++) {
    if (inp[i][j] == '#') {
      b = true
      if (i > 0) b = b && inp[i-1][j] == '.'
      if (i < H-1) b = b && inp[i+1][j] == '.'
      if (j > 0) b = b && inp[i][j-1] == '.'
      if (j < W-1) b = b && inp[i][j+1] == '.'
      if (b) {
        break;
      }
    }
  }
  if (b) {
    break;
  }
}
console.log(!b ? 'Yes' : 'No')