#1047 2004 · Google · Technology
Google put an unsigned math puzzle on a billboard and let it filter its own applicants
the problem
Resumes and cover letters made it hard to tell who could actually think like Google needed engineers to think
background
By 2004 Google was competing for the same engineering graduates every other tech company chased through the same channels — job boards, campus recruiters, referral programs — all of which filtered on credentials and self-presentation rather than the specific quantitative reasoning the job required.
Instead of writing a better job ad, Google put up billboards along Highway 101 in Silicon Valley and near Harvard Square carrying no company name and no explanation: just '{first 10-digit prime found in consecutive digits of e}.com', a pure math problem with nothing to click and no hint it was a job posting.
what everyone would do
Run the same recruiting channels as every competitor — campus info sessions, job boards, a slicker careers page — and hope a better pitch attracts sharper candidates than the identical pitch attracts everywhere else.
what they saw
A puzzle nobody was told to solve filters harder than any interview question, because only someone who already thinks that way would notice it, solve it, and chase the second problem with no promised reward in sight.
the move
Solving for the first ten-digit prime in the digits of e led to a website with a second, harder puzzle; only after cracking that second problem did the page reveal it was Google recruiting and invite the solver to submit a resume — the puzzle itself was the entire first-round screen, done before any human read a single application.
why it works
The billboard worked as a filter precisely because it withheld the payoff: nobody solving it knew a job was on the other side, so completion measured pure intrinsic problem-solving drive rather than eagerness to get hired, which a normal job posting can never isolate from the applicant's incentive to perform for the interviewer.
the payoff
NPR covered the stunt within days; it drew engineers who'd already proven, unpaid, the exact problem-solving Google's interviews tested for.
where it breaks
It only works once per audience — a copycat puzzle is old news the moment applicants start solving it because they already know a job is the reward, which turns intrinsic motivation back into performance for the interviewer, exactly what the original billboard was built to avoid.
what came after
The billboard became one of the most cited recruiting stories in tech, echoed in spirit by defense and intelligence agencies running their own cryptic puzzle recruitment; Google itself later built a persistent version, a hidden coding challenge that appeared inside search results for certain programmer queries.
references
- [1]Google Entices Job-Searchers With Math PuzzleNPR, 2004npr.org
- [2]The Time Google Enticed Job Applicants With a Math RiddleMental Floss, 2015mentalfloss.com