<div class=a></div>
<div class=b></div>
<div class=c></div>
<style>
  body {
    display:flex;
    justify-content:center;
    align-items:center;
    background: #F3AC3C;

  }
  .a{
    width:200px;
    height:200px;
    background:#1A4341;
    position:relative;
  }
  .b{
    width:100px;
    height:100px;
    background:#998235;
    position:absolute;
    bottom:50;
    left:100;
  }
  .c{
    width:50px;
    height:50px;
    background:#F3AC3C;
    position:absolute;
    bottom:50;
    left:150;
  }
</style>