CSS split four squares

圓形

.pie {
  background: conic-gradient(#FF5722 0% 33%, #FFEB3B 0% 66%, #2196F3 0% 100%);
  border-radius: 50%;
}

微軟logo

<div class="h-40 w-40" style="
    background: conic-gradient(#7cbb00 0% 25%, #ffbb00 0% 50%, #00a1f1 0% 75%,  #f65314 0% 100%;"
    >
</div>

參考

• 色票網站
• https://css-tricks.com/css3-gradients/
• https://www.sitepoint.com/create-css-conic-gradients-pie-charts/