11/20 100%, на проверку!!

svg {
border: 1px solid #dddddd;
}
polyline{
fill:none;
}

.polyline-1{
stroke:teal;
stroke-width:80;
stroke-linecap:square;
}

.polyline-2{
stroke:lightseagreen;
stroke-width:50;
stroke-linejoin:round;
stroke-linecap:round;
}

.polyline-3{
stroke:gold;
stroke-width:10;
stroke-linejoin:bevel;
}