CSS Border
BASIC HTML & CSS
<html>
<head>
<style>
.bubble {margin: 50px;
padding: 50px;
position: relative;
}
.bubble:after {
content: "";
position: absolute;
top: 100%;
left: 20px;
border-top: 20px solid blue;
border-top-color: inherit;
border-left: 20px solid transparent;
border-right: 20px solid transparent;
}
</style>
</head>
<div class="bubble" style="background: red; border-color: red;"></div><div class="bubble" style="background: green; border-color: green;"></div>
</html>
