Design

“Loop engineering” is a hot buzzphrase after mentions of it by Boris Cherny (Claude Code’s creator) and Peter Steinberger (OpenClaw's creator) went viral on social media. Loops are now a key part of how we get AI agents to iterate at length to build software. In this letter, I’d like to share my 3 key loops, shown in the image below, for building 0-to-1 products. These loops guide not just how I build software, but also how I decide what software to build. Agentic coding loop: Given a product specification and optionally a set of evals (that is, a dataset against which to measure performance), we can have an AI agent write code, test its work, and keep iterating until the code is bug-free and meets its specification. This idea of closing the loop took off around the end of last year, and it has been a game changer in enabling coding agents to work longer productively without human intervention. For example, over the weekend, I was building an app for my daughter to practice typing, and my coding agent could easily work for around an hour, using a web browser to check what it had built multiple times before getting back to me, without needing my intervention. The engineering loop executes quickly. Every few minutes, the coding agent might build and test a new version of the software. I hear frequently from developers who are finding new ways to engineer more effective engineering loops. This is an active area of invention! Developer feedback loop: In this loop, a developer examines the current product and steers the coding agent to improve it. Last year, a lot of developers (including me) were acting as the QA (quality assurance) function for our coding agents, manually finding bugs and then asking the agent to fix them. But with coding agents much more able to test their own code, the amount of time we need to spend on this function has decreased significantly. This allows us to make higher-level product decisions, such as what key features to offer, where the UI needs improvement, and so on. The developer-feedback loop operates over time intervals between tens of minutes and hours — that's how frequently a developer might review a product and give feedback. In the case of the typing app, I changed my mind a few times about the visual design, what cat costumes she can unlock as she learns (she loves cats), and the user flow for a grown-up to log in and steer the child's learning experience. When a developer has a clear vision for what to build, it is still a lot of work to translate that vision into a specification for a coding agent to implement. Further, after the developer has seen an implementation, they might update (or perhaps clarify) the spec to steer it toward what they want. If you find that the system repeatedly runs into certain problems, building a set of evals for the agent becomes useful. [Truncated for length. Full text: https://lnkd.in/gKDQ6H9s]

Demystifying the Software Testing 1️⃣ 𝗙𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝗮𝗹 𝗧𝗲𝘀𝘁𝗶𝗻𝗴: 𝗧𝗵𝗲 𝗕𝗮𝘀𝗶𝗰𝘀: Unit Testing: Isolating individual code units to ensure they work as expected. Think of it as testing each brick before building a wall. Integration Testing: Verifying how different modules work together. Imagine testing how the bricks fit into the wall. System Testing: Putting it all together, ensuring the entire system functions as designed. Now, test the whole building for stability and functionality. Acceptance Testing: The final hurdle! Here, users or stakeholders confirm the software meets their needs. Think of it as the grand opening ceremony for your building. 2️⃣ 𝗡𝗼𝗻-𝗙𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝗮𝗹 𝗧𝗲𝘀𝘁𝗶𝗻𝗴: 𝗕𝗲𝘆𝗼𝗻𝗱 𝘁𝗵𝗲 𝗕𝗮𝘀𝗶𝗰𝘀: ️ Performance Testing: Assessing speed, responsiveness, and scalability under different loads. Imagine testing how many people your building can safely accommodate. Security Testing: Identifying and mitigating vulnerabilities to protect against cyberattacks. Think of it as installing security systems and testing their effectiveness. Usability Testing: Evaluating how easy and intuitive the software is to use. Imagine testing how user-friendly your building is for navigation and accessibility. 3️⃣ 𝗢𝘁𝗵𝗲𝗿 𝗧𝗲𝘀𝘁𝗶𝗻𝗴 𝗔𝘃𝗲𝗻𝘂𝗲𝘀: 𝗧𝗵𝗲 𝗦𝗽𝗲𝗰𝗶𝗮𝗹𝗶𝘇𝗲𝗱 𝗖𝗿𝗲𝘄: Regression Testing: Ensuring new changes haven't broken existing functionality. Imagine checking your building for cracks after renovations. Smoke Testing: A quick sanity check to ensure basic functionality before further testing. Think of turning on the lights and checking for basic systems functionality before a deeper inspection. Exploratory Testing: Unstructured, creative testing to uncover unexpected issues. Imagine a detective searching for hidden clues in your building. Have I overlooked anything? Please share your thoughts—your insights are priceless to me.

💎 Accessibility For Designers Checklist (PDF: https://lnkd.in/e9Z2G2kF), a practical set of cards on WCAG accessibility guidelines, from accessible color, typography, animations, media, layout and development — to kick-off accessibility conversations early on. Kindly put together by Geri Reid. WCAG for Designers Checklist, by Geri Reid Article: https://lnkd.in/ef8-Yy9E PDF: https://lnkd.in/e9Z2G2kF WCAG 2.2 Guidelines: https://lnkd.in/eYmzrNh7 Accessibility isn’t about compliance. It’s not about ticking off checkboxes. And it’s not about plugging in accessibility overlays or AI engines either. It’s about *designing* with a wide range of people in mind — from the very start, independent of their skills and preferences. In my experience, the most impactful way to embed accessibility in your work is to bring a handful of people with different needs early into design process and usability testing. It’s making these test sessions accessible to the entire team, and showing real impact of design and code on real people using a real product. Teams usually don’t get time to work on features which don’t have a clear business case. But no manager really wants to be seen publicly ignoring their prospect customers. Visualize accessibility to everyone on the team and try to make an argument about potential reach and potential income. Don’t ask for big commitments: embed accessibility in your work by default. Account for accessibility needs in your estimates. Create accessibility tickets and flag accessibility issues. Don’t mistake smiling and nodding for support — establish timelines, roles, specifics, objectives. And most importantly: measure the impact of your work by repeatedly conducting accessibility testing with real people. Build a strong before/after case to show the change that the team has enabled and contributed to, and celebrate small and big accessibility wins. It might not sound like much, but it can start changing the culture faster than you think. Useful resources: Giving A Damn About Accessibility, by Sheri Byrne-Haber (disabled) https://lnkd.in/eCeFutuJ Accessibility For Designers: Where Do I Start?, by Stéphanie Walter https://lnkd.in/ecG5qASY Web Accessibility In Plain Language (Free Book), by Charlie Triplett https://lnkd.in/e2AMAwyt Building Accessibility Research Practices, by Maya Alvarado https://lnkd.in/eq_3zSPJ How To Build A Strong Case For Accessibility, ↳ https://lnkd.in/ehGivAdY, by 🦞 Todd Libby ↳ https://lnkd.in/eC4jehMX, by Yichan Wang #ux #accessibility

Smart materials in this futuristic design shift color and texture based on temperature, motion, or light — turning fashion into adaptive tech. Would you wear it? 🧬 This isn’t sci-fi. + Smart textiles are forecast to grow into a $17.6 billion industry by 2030, driven by innovations in nanomaterials, thermal sensors, and electrochromic coatings. + AeroSkin’s concept shows what happens when AI, material science, and design collide — and it raises the question: What happens when your clothes start thinking for you... 🎯 Imagine soldiers with adaptive camouflage. ⚡ Athletes wearing gear that adjusts cooling zones dynamically. 🌆 Or professionals using color-shifting jackets as expressive, data-driven fashion statements. We’ve made phones smart, homes smart, even cars autonomous… yet most of us still wear “dumb fabric.” Maybe the next frontier of computing isn’t a screen — it’s the skin you wear. #WearableTech #SmartMaterials #Innovation #FutureOfFashion #AI #ChameleonJacket #AeroSkin #TechDesign #MaterialScience #AdaptiveClothing

🪄 3D printing just broke free from gravity — and it happened at Disneyland Paris. Coperni, in collaboration with Disney Research, showcased a revolutionary technique called Rapid Liquid Printing (RLP) — a gel-based 3D printing process that allows objects to form freely in liquid space. The innovation: Instead of building layer by layer, RLP prints directly inside a gel bath. The gel supports the structure as it forms, meaning objects can be “drawn” in mid-air with smooth, continuous motion. What’s new: • No gravity constraints — objects print in all directions. • No supports or post-processing needed — a simple rinse finishes the product. • Compatible with soft materials like silicone and rubber, enabling flexibility and realism. Why it matters: This breakthrough eliminates one of 3D printing’s biggest limitations — the need for support structures. It drastically speeds up production, reduces waste, and enables designs that were previously impossible. → Fashion and luxury design — complex, fluid shapes in textiles and accessories → Architecture and furniture — organic, continuous forms without assembly → Healthcare and robotics — flexible components mimicking natural motion To me, this represents the next era of creation — where 3D printing stops stacking layers and starts shaping ideas in real time. Could this be the moment 3D printing becomes as intuitive as sketching in air? #3DPrinting #Design #Manufacturing #Creativity #FutureOfWork #Engineering #ArtAndTech

Hospitals are healing patients faster with 30-year-old Australian technology. Most healthcare facilities still operate in the dark. SolarTube skylights channel natural sunlight through reflective tubes directly into patient rooms and treatment areas. No electricity needed. Just free healing light all day. The healthcare transformation numbers: ↳ Faster patient recovery rates documented ↳ 15% staff productivity increase ↳ Reduced eye strain for medical professionals ↳ Lower patient anxiety during procedures Think about that. Tigoni Medical Center in Kenya installed SolarTubes in their COVID-19 facility. Healthcare workers reported less fatigue, increased alertness during long shifts. Patients showed dramatically improved morale and energy levels. At Rogaska Medical Center, natural daylight flooded clinics without unwanted heat. Staff comfort improved. Patient outcomes followed. Italian dental offices meeting occupational daylight standards found something unexpected: patients felt less anxious. Procedures became more comfortable. Natural light calmed nerves that fluorescent bulbs couldn't. Traditional Healthcare Lighting: ↳ Fluorescent tubes causing eye strain ↳ High electricity costs ↳ Artificial environments ↳ Staff fatigue increases SolarTube Healthcare Reality: ↳ Natural light reduces stress hormones ↳ Serotonin production increases ↳ Circadian rhythms regulate properly ↳ Recovery accelerates naturally But here's what stopped me cold: We're medicating depression while keeping people in artificial light. Jim Rillie invented this solution in the 1980s. Launched Solatube International in 1991. Now 2 million units worldwide bring natural light indoors. Healthcare facilities that adopt it see measurable improvements. Staff wellness increases. Patient satisfaction scores rise. Recovery times shorten. The Multiplication Effect: 1 hospital = hundreds healing faster 100 facilities = thousands of staff energised 1,000 installations = healthcare transformed At scale = medicine working with nature VCC in the UK experienced enhanced well-being building-wide. Staff and patients reported feeling calmer, healthier, happier. Simply from abundant daylight. We're not just installing skylights. We're installing wellness. One beam of natural light at a time. Follow me, Dr. Martha Boeckenfeld for innovations that heal environments and people. ♻️ Share if you believe healthcare should harness nature's healing power.

Do you know how to correctly set user personas for your product? What are user personas? Should both Prince Charles and Ozzy Osbourne land in the same user bucket? Well... It depends! A user persona is a made-up person representing a group of users in your product. It’s explicitly designed to help product teams understand their end users deeply by digging into their problems, goals, needs, pain points, behaviors, and preferences. The common misconception is that user personas are based on demographic data. While for some products this may be the right choice, this will usually be wrong and misguided. The user persona concept is not really about representing real people but representing a pattern of behavior. So, to correctly identify your user persona, you should not start with a name and a fake bio. Not at all! Instead, you need to dig deep into your product's analytics data and identify groups of users that interact with the Product in a similar manner. Thus, for example, for Spotify, you could identify the following groups: • Casual, free users • Paid users • Creators    Of course, you can go deeper and look for more granular personas within those main groups, but that's a story for another day. To the point, definitely, King Charles and Ozzy Osbourne would not fall into the same persona bucket. The King is most likely a Paid user, while Ozzy is a Creator. I can however imagine a Product, say about a medicine tracking app, where both Ozzy and Charles would fall under the same, "elderly, who need help to track their medicine intake" group, though they are very different people when you get to know them. And this is ok, again, user personas are about identifying patterns of behavior, not about any specific user, fictional or otherwise. Giving those patterns names and backstories has only one goal: To help you better communicate, to connect emotions and context to any problems the problem is built to fix :) Just like it helped to build this post! Just to add: knowing your demographics will help you build the right product, but it's not the same as crafting user personas. It will help you craft an imaginary user to closely match your typical user :) Do you agree with me? What are the product personas in your favorite product? Sound off in the comments! P.S. User personas are only a single tool in a Product Manager's toolbox. To learn more about other tools and how to become a Great product manager, visit www . drbartpm . com.

Datacenters are the foundation of our digital lives. They also create opportunities to demonstrate what’s possible when sustainability is treated as a design principle, not an afterthought. Teams around the world at Microsoft are tackling the energy and resource challenges of cloud computing head-on. In Europe alone, we’re implementing a variety of solutions: 🌱 Boosting biodiversity: Datacenters in the Netherlands are being designed with biomimicry principles, planting 150 native trees and 2,300 square meters of vegetation to restore habitats, improve water management, and reduce environmental impact. 💧 Saving water: We’re building datacenters in Spain with closed-loop cooling systems that fill once during construction and then continuously recirculate water between servers and chillers, eliminating the need for additional water and dramatically reducing consumption. 🔁 Cutting carbon: A new datacenter in Wales is being built using materials from a shuttered radiator factory, avoiding hundreds of tons of CO₂ emissions through smart reuse. ⚡ Stabilizing the grid: Across the Nordics, battery-backed systems help maintain steady grid frequency, making renewable energy easier to integrate and supporting a more resilient power supply. 🔥 Heating homes and businesses: Recovered heat from datacenters in Finland will help warm up to 250,000 homes and businesses through a municipal heating system. Denmark is setting up a similar system to extend the benefits of sustainable heating to more communities. Every day I am blown away by the creativity and ingenuity of these teams and our local partners. Check out these prime examples of this work. Read the latest story from Source to learn more: https://lnkd.in/gUtARfJ3 

This chart shows up in my feed every week. It's clean, it's confident, and it gives you the basic idea of what colors make us feel. Red means energy. Blue means trust. Pick the feeling, pick the color, done. But in branding, there's a lot more to it than that. Context, positioning, culture, history, audience perception, product category, and years of brand exposure matter more. Look at the chart's own examples. Red is supposed to mean romance. There is nothing romantic about Target, H&M, or a clearance sticker. The same red does completely different work depending on what sits around it. Color borrows its meaning. It borrows from the category, from the shapes next to it, and from whatever the competition already owns. Blue reads "trust" on a bank because banks spent decades training us to expect it, not because blue arrived with trust built in. Put that same blue on a fast food sign and it reads wrong. So when a client asks for a "trustworthy blue" or an "energetic red," the color is the easy part. The real work is figuring out what the color has to overcome, what it has to signal against the competition, and what the rest of the system is doing around it. Color is the part everyone sees. The thinking behind it is the part they don't. #Branding #ColorTheory #GraphicDesign #Marketing #ColorPsychology