Зачем атрибут stroke-miterlimit использовать?

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="100" height="600"
     xmlns="http://www.w3.org/2000/svg" version="1.1">
  <title> Лекция 5. Рисование</title>
  <desc>
    Пример stroke13.svg
  </desc>
  <line x1="70" y1="0" x2="70" y2="700" 
        stroke="black" stroke-width="1"/>
  <line x1="95" y1="0" x2="95" y2="700" 
        stroke="black" stroke-width="1"/>
  <polyline  points="10,30 70,50 10,70" 
             stroke="red" stroke-width="15"
             fill="none" stroke-linejoin="miter"
  stroke-miterlimit ="1" />
  <polyline  points="10,130 70,150 10,170" 
             stroke="red" stroke-width="15"
             fill="none" stroke-linejoin="miter"
  stroke-miterlimit ="2" />
  <polyline  points="10,230 70,250 10,270" 
             stroke="red" stroke-width="15"
             fill="none" stroke-linejoin="miter"
  stroke-miterlimit ="3" />
  <polyline  points="10,330 70,350 10,370"
             stroke="red" stroke-width="15"
             fill="none" stroke-linejoin="miter"
  stroke-miterlimit ="4" />
  <polyline  points="10,430 70,450 10,470"
             stroke="red" stroke-width="15"
             fill="none" stroke-linejoin="miter"
  stroke-miterlimit ="5" />
  <polyline  points="10,530 70,550 10,570"
             stroke="red" stroke-width="15"
             fill="none" stroke-linejoin="miter"
  stroke-miterlimit ="40" />
</svg>