Find The Invisible Cow
findtheinvisiblecow.com
A browser game where you move your mouse around a blank screen and the volume of the 'COW' sound increases as you approach the invisible cow hidden somewhere on the page — a classic of minimalist design.
Why it is useful
One of the purest examples of a one-mechanic game on the web. The audio-based gameplay is immediately understandable, the feedback loop is satisfying, and it takes about 30 seconds to complete — making it ideal for sharing. The game has been played by millions and spawned numerous imitators. A good answer to the question 'what can you make with just a sound and a click event?'