In 1952, the de Havilland Comet was the future.

It was the world's first commercial jet airliner. Sleek, pressurized, and twice as fast as anything else in the sky, it cut the London-to-Johannesburg trip nearly in half.

Passengers loved it. Britain had beaten America to the jet age, and the Comet was the proof.

Then they started falling apart.

In January 1954, a Comet broke up in mid-air near the island of Elba, minutes after takeoff. The fleet was grounded, inspected, and cleared. Three months later, another Comet disintegrated over the Mediterranean in almost identical fashion. No distress call. No warning. The aircraft simply came apart at altitude.

Investigators recovered wreckage from the seabed and did something unprecedented. They took an intact Comet fuselage and submerged it in a giant water tank, then repeatedly pressurized and depressurized it to simulate thousands of flights, compressed into weeks.

The fuselage failed. And when they examined exactly where, the answer was waiting in the corner of a window.

Every Comet had large, square windows. Under the cyclic stress of pressurization, the metal around those windows was developing microscopic cracks, and the cracks always started at the corners.

Here is the principle the Comet taught the world.

When stress flows through a material, it travels in smooth lines, like water through a channel. A gentle curve lets that stress glide around an opening. A sharp corner does the opposite. It forces all that energy to pile up at a single point. Engineers call it stress concentration, and at a 90-degree corner, the local stress can spike to several times the average load on the structure.

Pressurize and depressurize that corner thousands of times, and the metal fatigues, cracks, and tears. At 35,000 feet, a small crack unzips the aircraft.

The fix was just to round the corners. Distribute the stress. Give it nowhere to concentrate.

That single lesson escaped aviation and spread through the entire world. Every airplane window is an oval. So is every ship's porthole. Look at your phone. The screen has rounded corners. Your credit card. Swimming pool edges. Subway car windows. The cutouts in structural steel beams.

You are surrounded by rounded corners, and almost none of it is for looks.

It is the fossil of a lesson nobody needed to learn twice.

Prompt: Create a cinematic 3-frame sequential film stills (horizontal frames stacked vertically), full bleed edge-to-edge. Each frame should show a different moment from the same scene, with clear progression. Vary the composition, camera angle, and distances to create a sense of movement and storytelling. Use a cinematic, cooler-toned, high-contrast, deep-space blacks film with a natural color grade. Add subtle film grain, slight motion blur, and natural imperfections to emulate analog photography. Keep the composition candid and emotionally grounded, with a sense of movement and quiet storytelling. Overall aesthetic: cinematic, nostalgic, and organic, like raw film stills.

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PS—I wonder if the opposite approach is used for things intended to break to help facilitate the process.