<div class="box">
  <div class="box-inner">
    <div class="arrow bottom"></div>
    <div class="arrow top"></div>
    <div class="arrow right"></div>
    <div class="arrow left"></div>
  </div>
</div>

* {
  margin: 0;
  padding: 0;
}

body {
  padding: 15px;
}

.box {
  padding: 15px;
  background-color: #ffffff;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.arrow {
  display: inline-block;
  margin-right: 10px;
  width: 0;
  height: 0;
  /* Base Style */
  border: 16px solid;
  border-color: transparent #cddc39 transparent transparent;
  position: relative;
}

.arrow::after {
  content: "";
  position: absolute;
  right: -20px;
  top: -16px;
  border: 16px solid;
  border-color: transparent #fff transparent transparent;
}
/*bottom*/
.arrow.bottom {
  transform: rotate(270deg);
}
/*top*/
.arrow.top {
  transform: rotate(90deg);
}
/*left*/
.arrow.left {
  transform: rotate(180deg);
}
/*right*/
.arrow.right {
  transform: rotate(0deg);
}