Flappy Bird clones reportedly rolled in to the App Store at a rate of 60 games per day over the course of four days, according to numbers crunched by Pocket Gamer. The data comes from an investigation into 300 games that were deemed rip-offs of Dong Nguyen's former tap-to-flap mobile arcade game, averaging out to 2.5 clones arriving on the App Store per hour, or one per 24 minutes.
The data was pulled from games submitted between February 28 and March 3, and due to Apple's staggered release schedule, as many as 14 "Flappy" games arrived in the span of an hour at points. Pocket Gamer defined its use of the term "clone" in this case as "any game in which you guide some character through an obstacle course of pipes (or similar objects) hanging from the ceiling and sticking out of the ground." To be sure, Flappy Bird itself wasn't a particularly novel concept, but the rise in games that mimicked its exact style appeared to be unmistakable to the data gatherers.
Nguyen announced plans to pull Flappy Bird from the Google Play and App Stores on February 8, and later rationalized the decision by deeming it an "addictive product." After Nguyen pulled the game, indie developers participated in a "Flappy Jam" development challenge, which included entries from the likes of Super Hexagon creator Terry Cavanagh as well as punk band Fall Out Boy.