title: How to print a square using HTML (on a printer)?
body: <p>How to print a square <em>precisely</em> with 1 by 1 inch?</p>
  
  <p>I mean, <code>.strong { width: 1in; height: 1in; }</code> won't work! What really goes wrong? How to calculate this error?</p>
  
  <p>edit: everybody talks about screen pixel and the 1/72 ratio. What happens when it goes to the printer?</p>