If you solve this pencil riddle in 10 seconds, then your brain is sharp

How fast you solve this riddle could tell you whether you’re left- or right-brained. 

A visual riddle on TikTok has left some users confused about what seems like it should be a simple answer.

Ten pencils are lined up on a desk in four groups with a pencil width of space between groups.

The leftmost group has four pencils, then three, a pair of two and a single pencil.

The riddle asks the viewer to move one pencil in order to reverse the order of pencils so the rightmost group has four pencils and the leftmost group has just one.

The solution might come easier for left-brain dominant people.

[Warning: Spoilers below]

To solve the riddle, move the second pencil from the left group to the empty space in between the pair of two and the lone pencil. The number of pencils in each group is now ascending from one to four. 

A person’s ability to think with spatial reasoning is part of how easily they can find the solution.

Spatial reasoning uses your mind’s eye to think in three-dimensional space.

Children are typically first exposed to spatial reasoning using shape-sorting toys with pegs and corresponding holes. It’s a skill that can be improved upon.

Spatial reasoning skills are also used in everyday life, including when reading maps, assembling furniture or gadgets and in exercise or sports.

Researchers at the Institute of Education Sciences were awarded $1.6 million last year to investigate methods to educate children in these skills.

“Spatial reasoning is critical to student achievement, particularly in early math skills,” they wrote. “At later grades, it is a gateway skill to persistence in engineering, chemistry, geoscience and other STEM fields.”