<div></div>

div {
  height: 200px;
  width: 200px;
  
  border-top: 100px solid #EB37AC;
  border-bottom: 100px solid #FBAF29;
  border-right: 100px solid #00D497;
  border-left: 100px solid #4285F4;
  
  margin: 100px auto;
  transition: all .5s linear;
}

div:hover {
  height: 0;
  width: 0;
}