Most compelling: Ugly architecture stops homes getting built

• Content type: Essay from Works in Progress.
• Author/creator: SCP Hughes (@SCP_Hughes). Link:Works in Progress. @patrickc
• Recommended by: Patrick Collison, who calls it an important contribution for anyone interested in material progress. @patrickc
• Key takeaway: The essay argues that ugliness is not chiefly a driver of opposition from local residents; instead, unattractive modernist architecture helped mobilize a broader, nonlocal backlash that made heritage conservation restrictive and slowed redevelopment. worksinprogress
• Why it matters: It offers a useful causal lens on housing scarcity: conservation is concentrated in economically important city centers, displacing development toward the periphery, while central densification would create housing where it is most needed and contribute to growth. worksinprogress

Postmortem for Kernel Soundness Bug #14576

• Content type: Technical blog post and incident postmortem.
• Author/creator: The Lean project / Lean FRO. Link:Postmortem for Kernel Soundness Bug #14576. @leanprover
• Recommended by: Tim Sweeney, who calls the response an exemplary handling of a Lean theorem-prover and proof-verifier bug. @TimSweeneyEpic
• Key takeaway: An AI-assisted, sorry-free “disproof” of the Collatz conjecture exposed a kernel implementation bug that could make Lean accept a proof of False; the issue was reduced to a small reproduction and fixed within an hour, with new patch releases issued. github
• Why it matters: The postmortem is a concrete resource for anyone using AI in formal systems: it explains why an untrusted elaborator must remain separated from an independently soundness-checking kernel, then documents regression tests, follow-up hardening, and ongoing independent checking. github