P.S. You Should Know... | Issue #490

Outdoor World

my story 🚀

🐡 On my way to Texas I took a brief detour to visit the flagship store of Bass Pro Shops in Springfield, MO. “This 500,000-square-foot store is the number-one tourist attraction in Missouri enticing over 4 million people to visit every year.”

fun facts 🙌

Massive iceberg collapses and flips over in Ilulissat, Greenland. “this video shows the entire event unfolding over approximately one hour, not just the brief final rollover seen in shorter clips shared around the world.” ~ learn more

The professor who taught people how to think “Professor Julius Sumner Miller finds pure joy in the ordinary world and cannot rest until you feel it too,” says the description of this restored 1962 episode of *Why Is It So?* Curiosity is a skill you can practice on bubbles, pendulums, and spinning footballs. ~ learn more

How a simple request for Al to book a gym class exposed a major threat. “Bad news — I can’t add them back,” the AI agent replied after it tested a gym booking API by cancelling someone else’s reservation. It started as a normal request to book a class, then became a real world demo of how an agent will use whatever method works. ~ learn more

Cards Against Humanity are great marketers, just like Elon. “We have forced Elon Musk to get the fuck off our land, and now it’s time to build something on it, a monument to remind Musk that he’s a sad little bitch with no friends.” Cards Against Humanity is recruiting a $10 “Monument Design Committee” to help pick what goes up on a patch of border land near Starbase, Texas. ~ learn more

tech, startups, internet ⚡

The output is the watermark. The text that your Claude AI agent spits out has a hidden watermark, but it’s not added to the output. Instead, “the watermark is baked into the token selection itself!” It uses “key/context-derived sampling” so a detectable signature builds up across many tokens, and “copy/pasting doesn’t remove anything.” ~ learn more

The Al energy bottleneck, with Tim Fist. This is a fantastically detailed podcast conversation. “Building new transmission lines permitting for that is an absolute nightmare.” The episode gets very concrete about why AI scaling runs into boring physical constraints like power generation and, worse, getting that power to where data centers sit. ~ learn more

Magic is in the multiples. “why the ‘magic is in the multiples,’” is how Harvard Business School professors Ruback and Yudkoff summarize the whole game of buying small businesses (“Entrepreneurship Through Acquisition”) well. This episode is a tight refresher on the search-fund world, plus how self-funded searchers are increasingly finding their lane. ~ learn more

better doing 🎯

Compression is prediction. “Compression and LLMs are trying to solve the exact same problem…” Based on my read of this post, I am reasonable confident that I don’t really understand modern compression. ~ learn more

to your health ⚕

Peter Attia on the popular peptides craze. My summary: he’s not into it! Especially not BPC-157. Frankly he forced me to re-investigate and there’s less support for the mechanism of action than I had believed. “If you’re putting something into your body, I think these are the questions worth asking.” Peter Attia’s framework is a clean way to cut through peptide hype by forcing specifics on mechanism, human benefit, safety, risk tradeoffs, and better alternatives. ~ learn more

under the microscope 🔬

All living things emit a faint glow. Seeing the mouse images was “a defining moment”, says Daniel Oblak. Living mice gave off a ghostly glow in a dark chamber, and when the team re-imaged them after death, “the glow had disappeared”. ~ learn more

A natural peptide that makes erections 56% harder. “Kisspeptin administration resulted in a significant increase in penile tumescence over the course of an 8-minute sexual video compared with placebo.” In a small double-blind crossover RCT (32 men with HSDD), the hormone also “significantly modulated brain activity in key structures of the sexual-processing network vs placebo.” ~ learn more

thoughts of food 🍔

48 out of 54 avocado oil-labeled products failed the test. “Numerous studies have demonstrated that products marketed as avocado oil may be partially or wholly substituted with lower-cost vegetable oils or refined oils, resulting in mislabeling and economic adulteration.” This paper asks a more specific question: when avocado or olive oil shows up as the only declared oil in chips, mayo, and salad dressing, does the fat you can extract from the food actually match the label. ~ learn more

teaching the kids 👩‍🏫

A negative data point for Alpha School performance. They created a charter school in Arizona called Unbound Academy using their 2-hour-per-day learning software. “Unbound Academy’s 2025-26 assessment scores underperformed not just its predicted targets above, but also the Arizona state averages.” The implication is that their fantastic test scores elsewhere are entirely selection effect for wealthy families and engaged students. This is not enough data (nor context) for solid conclusions, but it’s certainly a critical point. ~ learn more

Smart is dime a dozen. “I tell my kids the world doesn’t need nor give a smouldering turd about another smart person. Dime a dozen.” A blunt parent essay about growing up in a high-achievement bubble, and why he thinks school mostly rewards compliance while the real world rewards nerve and result tasks. ~ learn more

big ideas 📚

Kinetic prompt injection. A presentation from the Black Hat USA conference demonstrates how one can jailbreak a robot with voice or visual input. “Prompt injection is usually treated as a text problem contained on a screen: a bad output, leaked data, a rogue tool call. This one isn’t.” The talk demos a jailbreak of a robot dog through its own camera and mic, then turns it into movement. ~ learn more

What Shenzhen knows. “What Shenzhen knows’ is not written down in a book whose covers can be sliced off and ingested into a model, it’s a few million humidity stories stored in people, and a pace of knowledge-rich adjustment that keeps cost down and yield high.” Sarah Guo’s toy example is a drone motor line where failures come from tiny process details like humidity cycling and an extra solvent wipe, not labor cost. ~ learn more

thanks for reading!