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Years ago, Everett Kroll's poor grades in elementary school worried his mother, Christine, who knew his struggles stemmed from being diagnosed with ADHD.

But today Christine is a proud mom — not just because her son's grades have improved, but also because he recently won top honors in the prestigious Intel International Science and Engineering Fair held in Pittsburgh.

Kroll, a junior at Stillwater Area High School, was among 1,800 high school students from 75 countries who participated in the world's largest international pre-college science competition held on May 17 in Pittsburgh. He walked away with the first place award in biomedical engineering for his prosthetic foot that he made from nylon on a 3-D printer.

"He [Kroll] was a squirrelly kid with ADHD. He would need counselors while he was in school. He would get partial and not-meeting-expectations grades. It was a concern for us," Christine said. "But now he made me proud."

The award netted Kroll $3,000 and this semester he earned a 4.1 GPA, boosting his overall GPA to 3.8, she said.

Kroll now views his ADHD as a blessing, as it helped him channel his energy into one subject.

"People think ADHD is bad. For me, if I lost focus on one thing, it helped me have hyper focus on another thing," said Kroll, 17, who took 20 months to invent his prosthetic foot.

His journey started in eighth grade when he took an engineering class through a national training program called Project Lead the Way. The next school year, he made it to the Minnesota state science fair with his tank made from Legos.

Later, as he decided to build a prosthetic foot, his mother objected because she didn't want him to focus on too many things at once.

"He wanted to pick up everything like you do in a buffet. I asked him to skip the science fair at least and slow down," she said.

Kroll refused. He said he felt strongly about everything he signed up for: he works at a shoe store, is a cross country runner, has served as a baseball umpire and is a karate black belt. He is also captain of his robotics team and participates in Science Olympiad and the Science Bowl.

The next science project began in 2017 and he went through 5,000 pages of research before making it to the international science fair in Los Angeles, where he won a special award for the prosthetic foot. This year he modified his product and won first place.

Aside from the hard work, the main challenge was to strike a balance in whatever he did. And for this, the family had to adapt to many things, like keeping a kitchen clock, in addition to taking medication. The clock timer, the mother said, made it possible to take breaks between different things that he was doing at the same time.

In achieving his goal, Kroll overcame many hurdles.

When he made his first design of the prosthetic foot, he thought he had achieved his goal. But it snapped and cut his foot the moment he stepped on it. It was only after 53 designs that he came up with the one that won him the prestigious award, followed by many internship offers.

He said that his simple prosthetic foot made for a person weighing as much as 300 pounds would cost between $10 and $15, depending on the person's level of mobility. The normal price, he said, can run in the tens of thousands of dollars.

"There is no electricity and no motor involved in the simple looking foot, yet it involves complicated concepts of applied physics and mathematics to create [a] Level 4 prosthetic that is 3-D printable," he said, explaining that Level 4 is the highest level of lower limb prosthetics and is capable of Olympic activity.

Kroll's room on the first floor of his house in Woodbury highlights his personality. His science interests are displayed on the wall facing the front window. A poster of Albert Einstein positioned next to a big periodic table of elements has the word 'GENIUS' spelled out of elements' symbols — Germanium (Ge), Nitrogen (N), Iodine (I), Uranium (U) and Sulfur (S). The room next door has been converted into a laboratory.

Those who have worked with Kroll describe him as someone who is "eager" and "determined" in whatever project he takes up.

"I admire his determination that I observed while working with him on the inexpensive prosthetic foot," said his mentor, Daniel Stubbs, a former 3M employee.

Kroll wants to own a patent of a prosthetic foot that is affordable, and he plans to go to college to study mechanical engineering before taking up a Ph.D. program.

After he completes his studies, he hopes to find a job with Fairview hospitals, 3M or Doctors Without Borders.

Gulam Jeelani • 612-673-4280