Hidden Links : Inventions and objects
Suggested age: Easy from age 7 · Medium from age 9 · Hard from age 10 · Expert from age 12
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How to play Hidden Links
Click three pictures on Easy, four on other levels. The game checks your group automatically when all pictures are selected. Click a card again to deselect it.
A correct group joins together with an explanation. A wrong selection is marked, then cleared so you can try again. Picture names stay visible at every level. Expert does not flag nearly correct groups.
Discovery mode allows unlimited mistakes, with no timer or account required.
Explore the links and their explanations
These notes reveal the answers. Open them after playing, or to learn before you start.
Measuring time
A sundial follows the Sun; an hourglass uses sand. Watches and clocks also measure time.
Learn moreObserving with lenses
Magnifying glasses, microscopes, binoculars and refracting telescopes use lenses to observe details or distant objects.
Learn moreCommunicating at a distance
Telegraphs send signals, telephones carry voices, fax machines send documents and walkie-talkies carry voices by radio.
Learn moreTravelling through the air
Hot-air balloons rise with warm air; aeroplanes and gliders have wings, while helicopters use a rotor.
Learn moreGenerating electricity
These devices turn energy from sunlight, wind, water or motion into electricity.
Learn moreRecorded sound media
Phonograph cylinders, vinyl records, cassette tapes and CDs are media that store recorded sound.
Learn moreFrequently asked questions
Is the game free without registration?
Yes. Games are free and progress is saved in this browser.
How do the four levels work?
Easy has nine pictures and names the groups. Medium has twelve with hidden groups. Hard has sixteen. Expert keeps sixteen and gives stricter feedback without flagging almost-correct groups. Names are always visible.
Is the daily puzzle the same for everyone?
Yes, at the same level. It changes at midnight in Paris. Results include the level and mistakes.