1. Always Ask, “What Happens If...?”

You can tear a poem apart to see what makes it tick.... You’re back with the mystery of having been moved by words. The best craftsmanship always leaves holes and gaps...so that something that is not in the poem can creep, crawl, flash or thunder in.

—Dylan Thomas, Poetic Manifesto, 1961

Dylan Thomas was a poet writing in the context of mid-twentieth-century Welsh society, but his thoughts on craftsmanship could be applied to just about anything, including our wonderful and complex profession of designing for the Web. Leaving room for unanticipated use is a thread that runs throughout the concept of being “bulletproof,” and in this chapter, we’ll reintroduce the topic by deconstructing a simple list of links found in the sidebar of our case study.