Proof of concept is a publication for designers, builders, and entrepreneurs—celebrating continuous learning, experimentation, and striving for achievement. "The 000 Series" is a collection of the top-rated content from the first 99 newsletter issues. From "WTF is a Product Designer?" to "Designing with metaphors and allegories," the range of topics by David Hoang. Subscribe to the newsletter to get $5 off. Note: This zine is a digital download and optimized as a PDF. You'll receive an email with a link to download the PDF.