.arrows {
width:300px;
height:100px;
position:relative;
background:
/* For the lines*/
linear-gradient(#000,#000) 10px 25px/2px calc(100% - 50px),
linear-gradient(#000,#000) 19% 20px/2px calc(100% - 30px),
linear-gradient(#000,#000) 50% 0/2px calc(100% - 2px),
linear-gradient(#000,#000) 70% 20px/2px calc(100% - 80px),
linear-gradient(#000,#000) calc(100% - 10px) 25px/2px calc(100% - 30px),
linear-gradient(#000,#000) calc(50% + 20px) 60px/ 40px 2px,
/*for the arrows*/
linear-gradient(to top left,transparent 50%,#000 0%) 10px calc(100% - 20px)/10px 10px,
linear-gradient(to top right,transparent 50%,#000 0%) 0px calc(100% - 20px)/10px 10px,
linear-gradient(to top left,transparent 50%,#000 0%) 20% calc(100% - 8px)/10px 10px,
linear-gradient(to top right,transparent 50%,#000 0%) calc(20% - 10px) calc(100% - 8px)/10px 10px,
linear-gradient(to top left,transparent 50%,#000 0%) calc(50% + 5px) 100%/10px 10px,
linear-gradient(to top right,transparent 50%,#000 0%) calc(50% - 5px) 100%/10px 10px,
linear-gradient(to top left,transparent 50%,#000 0%) 72% calc(100% - 58px)/10px 10px,
linear-gradient(to top right,transparent 50%,#000 0%) calc(72% - 10px) calc(100% - 58px)/10px 10px,
linear-gradient(to top left,transparent 50%,#000 0%) 100% 100%/10px 10px,
linear-gradient(to top right,transparent 50%,#000 0%) calc(100% - 10px) 100%/10px 10px,
linear-gradient(to top left,transparent 50%,#000 0%) calc(50% + 42px) 62px/10px 10px,
linear-gradient(to bottom left,transparent 50%,#000 0%) calc(50% + 42px) 52px/10px 10px;
background-repeat:no-repeat;
}
.arrows:before {
content:"";
position:absolute;
top:20px;
left:10px;
right:10px;
height:8px;
border:2px solid;
border-bottom:none;
border-radius:10px 10px 0 0;
box-sizing:border-box;
}
<div class="arrows"></div>