.red, .blue, .green{
  margin: 0.5em;
  height: 160px;
  border-radius: 4px;
  text-align: center;
}
.blue{
  width: 160px;
  float: right;
  background-color: slateblue;
}
.red{
  width: 240px;
  height: 240px;
  float: right;
  background-color: tomato;
}
.green{
  width: 160px;
  float: right;
  background-color: olivedrab;
}
.gray{
  padding: 0.8em;
  background-color: #eee;
}