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Technology Explained
What is actually happening inside the things you use all day — compression, encryption, positioning, the lot.
Modern technology hides its cleverness well. A photograph compresses to a tenth of its size, a phone knows where it is to within a few metres, a message crosses a hostile network unread — and all of it is invisible, which makes it feel like magic rather than engineering. It is engineering, and most of it rests on one good idea you can hold in your head. These pages take one such idea each and let you drive it.
In this series
Build a Wave to Kill a Wave
Noise-cancelling headphones don't block sound — they play an inverted copy of it. Delay that copy and watch cancellation turn into amplification.
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Enough Left to Read
A QR code hides spare Reed-Solomon codewords behind its pixels. Smudge it by hand or at random and watch exactly how much damage it survives.
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The Same Lie, Three Times
A GPS receiver's clock is cheap and wrong by an unknown amount, and every satellite range it measures inherits that same error. Drag one slider to cancel it and watch three near-misses collapse onto your exact position.
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The Pixel Is Three Lights
Every colour a screen shows is really red, green and blue lights glowing at their own brightness, blended by your eye into one. Drag a magnifying lens over a scene, or mix a colour yourself, and watch the three lights pull apart.
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What the Eye Never Missed
A photo is secretly 64 fixed wave patterns repeated over every 8×8 block. Drag the quality slider and watch JPEG throw away the ones your eye wouldn't miss.
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The Wheel That Runs Backward
A spinning wheel filmed at a fixed frame rate can look frozen, crawling, or spinning the wrong way. Set the true speed and the sample rate yourself and watch the exact moment it flips.
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The Rarest Two, Every Time
Type anything and watch Huffman's 1952 trick build its own code: merge the two rarest symbols, every round, until the commonest letters end up with the shortest bits.
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A Secret Nobody Sent
Two people who have never met agree on a secret key while a stranger hears every word between them. Mix it in paint, then do it properly with a prime — and set the eavesdropper loose to try every key there is.
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The Error Names Itself
Sixteen bits go down a wire, one arrives wrong, and there is nobody to ask for a resend. Flip any bit and four parity checks spell out its address in binary; flip two and watch the code notice that it can no longer be sure.
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The Shape of a Secret
One message, three machines: Caesar, Vigenère, Enigma — with a live count of its letters underneath. Watch the fingerprint of English flatten into noise, then break the first two ciphers from the frequencies alone.
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