A riddle for the more attentive: can you guess which container will fill up first?

A faucet, pipes, seven containers… It’s a seemingly simple question: which one fills up first? This type of puzzle is popular because it requires less calculation than careful observation. The key here is to resist the temptation to follow your instincts and follow the water’s path, as if you were a drop about to fall into the circuit.
The correct method: observe before concluding.

In front of the diagram, start with three golden reflections:

Look for obstacles: valves, plugs, pipes that are too high… So many barriers that are invisible at first glance.

Read the slope of the circuit: the water obeys the force of gravity and chooses the most direct and least steep path.

Compare lengths: For the same capacity, the shortest route almost always wins, especially if it has fewer bends and branches. Keep in mind that until a container is full to the drain (overfilled), it acts as a dead end that does not feed the next line.

The classic trap: not all pipes are “open.”
The puzzle often hinges on minor details: a blocked section, a drain located above the liquid level, an elbow that rises too high. The result: the branches look promising but don’t let anything through. This is what confuses most people who respond too quickly.