<div class="grid">
  <!-- 1ST ROW -->
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <!-- 2ND ROW -->
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <!-- 3RD ROW -->
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <!-- 4TH ROW -->
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <!-- 5TH ROW -->
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
  <div class="tr-down gold-down"></div>
  <div class="tr-up silver-up"></div>
</div>

/* Shape snippets taken from: https://css-tricks.com/the-shapes-of-css/ */

body { 
  align-items: center;
  background: #f99991; 
  display: flex;
  height: 100vh;
  justify-content: center;
}

.grid {
  background: #efefef;
  border-radius: 40px;
  -webkit-box-shadow: 10px 10px 26px -6px rgba(168,100,96,0.6);
  -moz-box-shadow: 10px 10px 26px -6px rgba(168,100,96,0.6);
  box-shadow: 10px 10px 26px -6px rgba(168,100,96,0.6);
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr 1fr;
  grid-template-rows: 1fr 1fr 1fr 1fr 1fr;
  margin: auto 0;
  overflow: hidden;
}

.tr-up {
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-top: 100px solid red;
  height: 0;
  width: 0;
}

.tr-down {
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-bottom: 100px solid red;
  height: 0;
  width: 0;
}

.silver-up {
  border-top-color: #c5bcbd;
}

.gold-down {
  border-bottom-color: #e8c363;
}