Practical iO should not be a problem only for “iO specialists.” We want researchers and engineers from FHE, ZKP, and MPC to be able to contribute to making iO practical. In this explainer, we present concrete remaining challenges in Diamond iO that different communities can work on using their existing expertise: The point is that practical iO breaks down into several concrete bottlenecks, including: * making FHE evaluation over BGG+ encodings practical; * scaling input size without exponential noise growth; * cryptanalyzing the non-standard lattice assumptions behind Diamond iO; * designing proof systems whose verification is cheap over BGG+ encodings; * building distributed obfuscation without making the obfuscated circuit size scale with the committee size. If you work on FHE, ZKPs, MPC, lattice-based cryptography, or cryptanalysis, there is likely a concrete part of the practical iO roadmap where your expertise can matter. We are also launching ObfusBench as a public leaderboard and obstacle tracker for iO efficiency: The goal is to make progress visible, comparable, and attributable: when someone improves one component, we want that improvement to show up in end-to-end estimates under a common framework. Practical iO is still far away, but it is becoming a much more modular and collaborative engineering/research problem.