Easter Eggs

Looking closely, some interesting details emerge from the books. This list may be incomplete:

AART

 * The endpapers in many editions show a range of easter eggs:
 * Buildings spell out "Knowing something is a bad idea does not always decrease the odds that you will do it". This quote served as a basis for the endpages design
 * The design is also based on a map of Lower Manhattan
 * Right to the second "N" of "knowing", the building has the logo of Hank's company Complexly
 * On the building of "O" in "not", the endpage designer TEKST put their signature
 * Just under the "B" of "bad", the building features a (hex) code "25d067"
 * Two buildings below "is", there’s the Nerdfighter symbol
 * The building between the "Y" of "you" and "D" of "do", the building has "DFTBA" written on it
 * The cover has two hidden messages in small print:
 * Above the "T" in "Thing", it reads "how far will we go?"
 * Under the first "E" in "Green", it reads "how long will we last?"
 * The Carl between the "G" in "Thing" and the "N" in "Green" is the only one to have eyes
 * In a tweet, April uses the Amazon link http://amzn.to/2ElGwTL to get people to buy her book. In real life, this is an easter egg and joke, and it redirected to an Amazon Affiliate Link with the tag "vlogbrother09-20". The page is no longer available, but an archived version reveals the product was Natural Water-Based Lubricant, 55 Gallon Drum/7040 Fl Oz (archived link) by Passion Lubes.
 * The word “deadpanned” appears exactly once in the book - another tribute to the books by Hank Green's brother John, because John does that in each of his book.
 * Tulip man is most likely a reference to An Imperial Affliction, a fictional book in The Fault In Our Stars by John Green
 * Prior to the release of the book, the Twitter account @AprilMaybeNot released some posts related to April May's character
 * Peter Petrawicki also has a Twitter account

ABFE

 * Prior to the release of the book, and prior to the official release of the cover, Hank Green organised a small internet scavenger hunt for the cover:
 * Some versions of the temporary cover featuring only the book title and author name also had a faded text in small print reading "yes, very sneaky, but what twitter handle should you follow?"
 * Going to @YesVerySneaky on Twitter revealed a cropped part of the book cover as the avatar
 * Putting together the first letters of the videos posted on @YesVerySneaky lead to hankgreen.com/cover (archived link) with the full book cover
 * Before the scavenger hunt started, there was some very brief confusion over the book title, with publishers naming it "A Beautifully Foolish Endeavor" and Hank calling it "A Beautifully Futile Endeavor", which was revealed to be an earlier title and a mistake
 * Penguin Random House created a Altus themed website with resources for ABFE with AltusFuture.net
 * The link in the book to April's new video leads to Hank's cover of Never Gonna Give You Up by Rick Astley HANKROLL'd
 * Kurt Butler's business card
 * Calling the number (856) 294-6319 reaches Kurt Butler's voice box and callers can call a message. Hank is known to listen to messages through Google Voice
 * EarthforgeMinerals.com redirects to an Amazon page to a "Trans Rights Are Human Rights" t-shirt. This redirect was created by a fan.