This just caught my eye while reading this thing. At first I searched for the image, but to my surprise it was all about CSS sorcery:
<html> <head> <style> .postit { position: relative; display: inline-block; width: 250px; border-bottom-right-radius: 36px 12px; padding: 15px 15px 10px 10px; border: 1px solid #e0dcbf; background-color: #fff8dc; margin-bottom: 12px; } .postit::after { content: ""; display: block; position: absolute; width: 80%; height: 30px; bottom: 18px; right: 18px; z-index: -1; transform: rotate(3deg) skew(8deg); box-shadow: 13px 18px 6px rgba(0,0,0,0.3); } </style> </head> <body> <div class="postit">text</div> </body> </html>