- Discussion of photon sieves as a method for focusing soft X-rays to spot sizes smaller than the diameter of the smallest pinhole, with a reference to a 10^7-hole optical photon sieve and a suggestion to use a focused ion beam (FIB) for fabrication.  
- nmz787 shared links to recent papers on visible-wavelength planar metalenses and provided GitHub code for designing diffractive lens nanopillar outlines using OpenCV.  
- kanzure posted a link to the Bulletproofs paper, a non-interactive zero-knowledge proof system with short proofs and no trusted setup.  
- A tweet was shared linking to a new leaderless replicated state machine protocol paper, described as an alternative to traditional consensus algorithms.  
- razzy raised a question about mammal-fungi symbiosis, prompting brief, humorous responses from other participants.  
- kanzure referenced an open letter proposing a change to Bitcoin’s proof-of-work algorithm, indicating ongoing debate within the cryptocurrency community.