<?xml version="1.0"?>

<!DOCTYPE donutBoxes [ 
  <!ELEMENT donutBoxes (donutBox+)
  <!ELEMENT donutBox (yeast?, cake*, ((creme | SUGAR)+ | glazed)+)> 
  <!ELEMENT yeast #EMPTY>
  <!ELEMENT cake #EMPTY>
  <!ELEMENT creme #EMPTY>
  <!ELEMENT sugar #EMPTY>
  <!ELEMENT glazed #EMPTY>
]>

<donutBoxes>
  
  <donutBox>
    <yeast />
    <cake />
    <glazed />
    <creme />
  </donutBox>
  
  <donutBox>
    <yeast />
    <cake />
    <creme />
  </donutBox>
  
  <donutBox>
    <SUGAR />
  </donutBox>
  
  <donutBox>
    <yeast />
    <cake />
    <cake />
    <cake />
    <glazed />
  </donutBox>
  
  <donutBox>
    <glazed />
  </donutBox>

  <donutBox>
    <yeast />
    <cake />
    <cake />
    <cake />
    <creme />
    <creme />
    <SUGAR />
    <creme />
  </donutBox>
</donutBoxes>

