At first glance, this light-bulb puzzle looks like an ordinary three-by-three arrangement. Count the obvious bulbs and you will get nine. But the picture includes more than the large ones.
How many light bulbs can you find?
There are 12 light bulbs in total. Nine large bulbs form the main layout, and three smaller bulbs are hidden in the spaces between them.
Where are the extra bulbs?
Look to the right of the bulb near the upper-left corner. Then check beside the center bulb in the middle row. Finally, inspect the gap to the right of the lower-middle bulb. The smaller lights are partly obscured by their larger neighbors.
The size difference is what makes this visual challenge work. Your eyes quickly recognize the regular grid, and your brain may decide that the counting is finished before you have checked every gap.
A simple attention challenge
Try looking at the picture once for ten seconds, then look away and give your answer. On the second viewing, slow down and search the spaces between the main objects.
Did you notice all twelve immediately? Pass the puzzle along and see whether a friend can find the three hidden light bulbs.
