This SVG example demonstrates how to create a quadratic chain path.

QuadraticChainPath.svg

<svg width="220" height="220" xmlns="http://www.w3.org/2000/svg">  
  <path d="M10,110 Q10,10 110,10 T210,110 T110,210 T10,110"
    fill="none" stroke="black" stroke-width="1"/>
</svg>

Output