md opacity

const MdOpacityIcon = (props) => (
  <svg 
    xmlns="http://www.w3.org/2000/svg" 
    viewBox="0 0 24 24" 
    width="24"
    height="24"
    fill="none" 
    stroke="currentColor" 
    strokeWidth="2" 
    strokeLinecap="round" 
    strokeLinejoin="round" 
    {...props}
  >
    <path d="M24 0H0v24h24V0zm0 0H0v24h24V0zM0 24h24V0H0v24z" fill="none"/><path d="M17.66 8L12 2.35 6.34 8C4.78 9.56 4 11.64 4 13.64s.78 4.11 2.34 5.67 3.61 2.35 5.66 2.35 4.1-.79 5.66-2.35S20 15.64 20 13.64 19.22 9.56 17.66 8zM6 14c.01-2 .62-3.27 1.76-4.4L12 5.27l4.24 4.38C17.38 10.77 17.99 12 18 14H6z"/>
  </svg>
);