The last 747 draws a picture with its flight path. And, yes, there's a way to (sort of) connect this to appsec.
There's a long history of easter eggs in software, including from well-known Seattle-area companies. Plus an even longer history of ASCII art in command line tools, source code, and zines.
Lots of early hacking groups used ASCII art in their web sites and advisories. You can see some grand examples from the Cult of the Dead Cow. There were similar groups to come out of the 90s like w00w00 and TESO.
SQLMap, which I highlighted in our tool segment last episode, uses ASCII art for its logo.
And for those of you looking for practical applications of ASCII art, you can even turn markdown into diagrams with Mermaid. ASCII diagrams are a big part of many RFCs.