byte into another byte

[gfvalvo]

  byte copyfrom[] = {0b0, 0b1010, 0b0};
  byte pastein[] = {0b10010101, 0b01010111, 0b01100000};

  pastein[2] = (pastein[2] & 0b11110000) | (copyfrom[1] & 0b1111);