SOURCE

<div class="box">
    <div class="left"></div>
    <div class="right"></div>
</div>

.box {
    display: flex;
    margin: 100px;
}
.left {
    position: absolute;
    width: 100px;
    height: 170px;
    border: 2px solid red;
    border-left: 0;
    border-bottom: 0;
    transform: rotateY(180deg) translateX(50px) rotateZ(45deg);
    border-radius: 40% 50% 0;
}
.right {
    position: absolute;
    width: 100px;
    height: 170px;
    border: 2px solid red;
    border-left: 0;
    border-bottom: 0;
    transform: rotateZ(45deg);
    border-radius: 40% 50% 0;
}