That's what people ordinarily assume I mean, but while our work sample challenges were similar to the cryptopals and Microcorruption stuff, they were not the same, or even derived from them. They were designed specifically to qualify candidates, and in fact predated our public challenges.

Just to further clarify, by work sample you do NOT mean an example of previously produced work? This still seems fickle: my dozen years of work output (for example, building and running a site with perfect uptime for millions of users) is not as valid an indicator of my future performance as how I happen to score on some arbitrary timed test?

Absolutely not. Samples of previous work are deceptive at the best of times.

Ahh, interesting. Would you mind sharing an example of how they were different, or how the fact that they were specifically for qualification changed the thought process? I'm working on making tech interviewing better and am fascinated by this stuff.

NDAs? Everything I've done yet is proprietary and judiciously covered by various binding legal agreements.

I wouldn't breach such a contract nor should you hire someone that would be willing to do so. The sole exception being in the cases where it would be the best for the public interest, i.e. whistle-blowing.