Washington: A college dropout has become an expert at maths and physics — after being punched in the back of the head.

Jason Padgett was a party-loving 31-year-old American who wore his hair in a mullet and made a living working in his father’s furniture shop when he was mugged in a karaoke bar near his home in Tacoma, Washington, in 2002.

He was knocked out but released from hospital the same day, unaware that he had suffered a profound brain injury. The next day he woke up and found that his vision had changed to include details he never spotted before. Turning on the bathroom tap, he noticed “lines emanating out perpendicularly from the flow”.

“It was so beautiful that I just stood in my slippers and stared,” he said.

Suddenly he could see elaborate geometric shapes in every day objects. These endlessly repeating patterns are known as fractals and are regarded by mathematicians as the building blocks of everything in the known universe.

That led to an obsession with maths and physics. Not only that, he had the ability to recreate the fractals by hand in extreme detail, despite having no previous talent for art. Some took him months to create.

Padgett, now 43, has since been diagnosed as one of only 40 people in the world with acquired savant syndrome, in which once-ordinary people become skilled in maths, art or music after a brain injury.

At first he was frightened by his new ability. He stopped going to work and spent all of his time at home, refusing visitors. He became obsessed with germs and would wash his hands until they were red, and wouldn’t even hug his own daughter until she washed her hands as well.

But after seeing a documentary on savantism he contacted leading expert Dr Darold Treffert, who diagnosed him with “acquired savant syndrome”.

Further research found that the left side of his brain was more activated, especially in the area we use for mathematics.

It seems that after his injury, neurotransmitters flooded the left side of his brain and ultimately changed its structure, making him hyper-specialised.

Padgett has now returned to college and written a book, Struck By Genius. In it, he writes: “I believe I am living proof that these powers lie dormant in all of us.

“If it could happen to me, it could happen to anyone.”