Prototype #4 failed before it was ever assembled. What followed wasn’t a simple fix, but an investigation into leather bookbinding tolerances and how narrow spacing, tool limits, and material choices interacted under constraint. This piece documents that failure and what it revealed about craft, systems, and learning. On February 06, 2026, Prototype #4 categorically failed before it was assembled. Oof, that hurts. Instead of licking my proverbial wounds, I'm going to walk you