Explore tools for transforming informal mathematics into formal mathematics and vice versa in this 42-minute lecture by Patrick Massot from the Hausdorff Center for Mathematics. Discover how the Lean blueprint infrastructure facilitates collaborative formalization projects and learn about its potential adaptability to other proof assistants. Gain insights into the ongoing development of Informal Lean, a tool designed to convert Lean statements and proofs into customizable informal mathematics, allowing readers to select their preferred level of detail.