So that's why I find it so fantastic!

Even better: Tetris Shelves!

Playing the video game Tetris could reduce the symptoms of post-traumatic stress disorder, British scientists have claimed.

Experts from Oxford University found the block-dropping action can positively alter the way negative thoughts are created after a distressing event.

This means it could help prevent flashbacks and other unwanted traumatic memories.

Researchers from the university's psychology department tested a group of people with no previous mental health problems.

They were all shown a video containing disturbing images such as fatal road accidents and human surgery.

Then 30 minutes later, the participants were split into three groups. One played Tetris, one played a game called Pub Quiz and the third was told to just sit quietly.

During this 10-minute period, the scientists found those in the Tetris group reported the fewest number of flashbacks compared to the other two groups.

They were also asked to keep a flashback diary for a week and those who had played Pub Quiz experienced significantly more than any others.

The authors concluded that engaging in a visual task like Tetris can be protective after a traumatic event because it interferes with the brain's ability to lay down visual memories - the same harrowing images that could later return as flashbacks.

A further test left a gap of four hours between the participants watching the video and playing the game but the same results were found.

"We account for this based on current models of memory consolidation indicating that certain types of memory may be malleable for up to six hours," the authors noted.

The researchers suggested that with even more research, Tetris, or a visual-spatial task like it, could be developed as a kind of "cognitive vaccine" against flashbacks.

This could be used as an alternative to current forms of treatment for post-traumatic stress disorder which are most commonly drug treatment or counselling.

Tetris was developed in 1984 and has sold hundreds of millions of copies worldwide.