Pendulum Wave 3D vs Nothing but Primes

Eighteen pendulums, released at the same instant. A perfect line for a moment — then a wave, a fold, then no pattern at all. Sixty seconds later, a perfect line again. None of that is luck. Every pendulum is given a length that makes it swing an exact whole number of times per cycle, so the scattered part was never really a mess. It was the middle of a return. It is not a looping video, and not an animation faked to look about right. It is a live physics simulation, computed frame by frame while you watch. NOBODY WROTE THE MUSIC Turn the sound on, and each pendulum rings a note once per full swing, as it crosses the bottom — higher for the short ones, lower for the long ones. Only five notes of the scale are used (do, re, mi, so, la), spread across octaves, so they stay clear no matter how many sound at once. There is no composer here. The lengths are the melody. The moment everything lines up is the quietest one — all eighteen are at the far end of their arc, none of them crossing the bottom. A breath later, eighteen notes come down in a run, high to low, in under a fifth of a second. You are hearing exactly what you are watching. ANY ANGLE YOU LIKE Drag to put the camera anywhere. From an angle, a row of swinging pendulums. From directly above, a wave running along the row. The motion never changes. The angle does all the work. Four layouts: a straight Line; a Circle, where the wave travels around the ring; a Spiral winding outward; and a Grid, where the swing spreads like woven mesh — the more pendulums you add, the clearer the weave. Four color themes — Cool, Neon, Mono, Sunset. The bobs glow softly. Turn on Light trails in the Display panel, and each one leaves a line of light hanging in the air behind it. CINEMA MODE One tap: the controls disappear, the camera begins a slow orbit, and the ad goes with them. A waiting room screen, a tablet on the edge of a desk, a dark room late at night. It becomes something to look at, and nothing else. ALSO INSIDE • Set the number of pendulums, the cycle length, the swing angle and the speed • Save any setup you like as a preset • A data panel listing every pendulum's swings, length and period • "How it works" — the real explanation, in plain words, no equations • Available in 33 languages • No account, no sign-in. iPhone and iPad ABOUT THE ADS The app is free. There is one small banner at the bottom of the screen — no full-screen ads, no video ads — and in Cinema mode even that banner disappears. Before the first ad, the app asks you — on iPhone and iPad for permission to track; in Europe, a consent screen comes first. Accept, and ads may be matched to your interests; decline, and the banner still appears, simply unmatched. You can change your answer later: the consent in the app's settings, the tracking permission in iOS Settings. The app itself never asks for your name or email. To show the banner, Google AdMob uses standard advertising data (an advertising identifier and approximate location derived from your IP). See our Privacy Policy for details. Don't stop watching while it is scattered. Stay until it lines up again.

Numbers sink through deep water. As they sink, they come apart into their prime factors. 12 becomes 2 and 2 and 3. The primes drift to a number line at the edge of the screen, light up, and pass on. Some numbers do not come apart. Divisible only by 1 and themselves — primes. Those stop where they are and glow amber. - You do nothing No arithmetic. Tapping does not make anything go faster. There is no winning and no ending. Touch the screen once to begin, and then watch. - The number line is walked, not sampled Numbers are not thrown out at random. They are taken in order, one at a time, from 2. So twin primes — two apart — and prime deserts, long stretches with none at all, appear exactly as they really are. Nothing here is staged. - Amber means prime That colour is used nowhere else in the app. You do not have to learn which numbers are prime. The glowing ones are. - A codex When a number with some property drifts past, a card is added. Taxicab 1729, perfect numbers, amicable numbers, Mersenne primes, prime deserts, the sieve of Eratosthenes, semiprimes and RSA — twenty in all. Every prime you have passed, and the whole number line you have walked, stay readable. - You can slow it down You can make it faster, and you can always put the speed back to how it began. Nothing you have built up is lost by doing so. - It stops, eventually When the numbers grow too large, the app stops. Either it reaches the edge of what a 64-bit integer can hold, or it meets a number it cannot factor within the work allowed. Calling something prime when it is not known to be prime is not an option, so it stops and tells you why. That place is the foot of the wall the internet's encryption stands on: instant to multiply, forbidding to take apart. Everything is computed on your device. The network is used only to show ads.