I always assumed it was created with html/css. After all it is just a capitol Y.

``` <a class="logo" href="https://news.ycombinator.com">Y<span class="sr">combinator Logo</span></a> ``` ``` .logo { display: block; width: 18px; background: #ff6601; border: 1px solid white; color: white; text-align: center; ```