JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a"><div class="b">10</div></div>

CSS

.a {
  position: relative;
  width: 50px;
  height: 50px;
  margin: 50px;
  border-radius: 10px;
  line-height: 50px;
  text-align: center;
  font-size: 18px;
  color: #fff;
  background-color: red;
  transform: rotate(-45deg);
}
.b {
  transform: rotate(45deg);
}

 .a::after {
   content: '';
   position: absolute;
   border-radius: 10px;
   border: 1px solid red;
   box-sizing: border-box;
   top: -10px;
   left: -10px;
   width: 70px;
   height: 70px;
 }
 
 .a::before {
   content: '';
   position: absolute;
   border-radius: 10px;
   border: 1px solid red;
   box-sizing: border-box;
   top: -5px;
   left: -5px;
   width: 60px;
   height: 60px;
 }