Students roaming the halls of the College of Engineering may think they are seeing double.

And they are - in the form of two sets of identical twins.

Sisters Karsten and Kristen Bush, both graduating seniors, are studying chemical engineering. Brothers Conner and Daylen McDaniel, both juniors, are majoring in aerospace and mechanical engineering, respectively.

The two sets of sisters and brothers are inseparable - living together, riding to campus in the same car and sharing similar interests - but that's just fine with them.

"You always have a friend," said 23-year-old Kristen, who is 52 minutes younger than her sister. "When you have a twin, you have this connection you don't experience when you don't have a twin."

Karsten feels the same.

"It's cool that you can have someone to do random stuff with," she said.

For 20-year-olds Daylen and Conner, it's similar but with a little good-natured ribbing about putting up with each other no matter how they behave.

"You can do anything you want, and it does not matter," said Daylen, who is one minute younger than his brother.

Aside from DNA, they have a lot in common.

Their moms dressed them in matching outfits when they were little - though in different colors. Now, if they happen to be wearing a similar look, it's unintentional.

"It does still happen that we end up dressing the same," Daylen said. "I will say, 'Go change. I got dressed first.'"

Both sets of twins shared classes growing up, but they never tried to fool the teacher.

"The closest we came was when we changed seats and laughed to ourselves thinking it was a big deal, but it was not," Karsten said.

Even though they are identical twins, Kristen said it's hard for her to see the resemblance when she looks at her sister - even with the same dark brown, almond-shaped eyes and similar bright smiles. Karsten has a distinctive dimple in her right cheek.

Beyond physical appearance for the siblings, many of their interests align.

The Bushes got interested in engineering in high school. The McDaniels come from a long line of engineers.

Daylen and Conner enjoy tinkering with a Mini Cooper that they turned into a race car. They both love horses, and their family owns several steeds. They used to work side by side on desktop computers at home. Now, their computers are in separate rooms, and they call each other on the phone when they want to ask questions.

Daylen works at the Native American Cultural Center. Conner doesn't have a job, but he can sometimes get his brother to loan him a few bucks. At last tally, he owes Daylen $18.

Karsten, who works for University Housing Services, and Kristen, a student assistant for the Maximizing Engineering Potential (MEP) program, are involved in a few clubs separately but mainly do things together, sharing a love of roller-skating and Netflix. They still share a room.

"We are kind of stuck like glue," Karsten said.

Like notable look-alikes such as pro wrestlers Nikki and Brie Bella, child stars Ashley and Mary Kate Olsen and astronauts Mark and Scott Kelly, the Bushes and the McDaniels share a similar career arc.

For Daylen and Conner, the pull toward engineering is in the bloodline.

"We traced our lineage, and in our family, engineers go back 100 years," Daylen said.

Their paternal grandfather was an engineer. Their dad doesn't have a degree in engineering, but he has a business fabricating machine parts and fixing them.

Their older brother was a student at Cal Poly Pomona when the Riverside natives opted to apply to the only school they really considered. Conner chose aerospace engineering because he likes airplanes. Daylen, a fan of cars, opted for mechanical engineering.

Karsten and Kristen became interested in engineering at Fullerton Union High School.

"I had a cool chemistry teacher. I also had a physics teacher who said, 'You should be an engineer,'" Karsten said. "I made a list of all the disciplines in engineering, complete with salaries and what they do."

Kristen said she had a similar experience, with that same physics teacher seeing her interest in alternative fuels and encouraging her to consider studying engineering.

They chose Cal Poly Pomona to be close to home.

Lily Gossage, director of MEP, knows all four students.

Both sets of siblings are in MEP, a recruitment, recognition and retention program that started in 1982 for underrepresented and low-income students in engineering. Bryce, the older brother of Daylen and Conner, is a mechanical engineering senior, a member of MEP and once served as the student president for the American Indian Science and Engineering Society (AISES), of which Gossage serves as the advisor.

All four twins also went through the Engineering in Your Future summer residential program, which includes a three-day stay on campus for incoming engineering students.

"These two pairs are very close," Gossage said. "They go everywhere on campus together. If I don't see them together right then, then I see them together later."

Gossage describes all four as respectful and giving. For those who come from underrepresented groups - the Bush sisters are African American and the McDaniel brothers part Native American from the Pascua Yaqui tribe - feeling isolated can be an issue, so MEP encourages students to lift each other up, she said. The twins have both the program and their built-in support system to rely on.

"They finish each other's mind thoughts," Gossage said. "They will never be alone."

Once Karsten and Kristen graduate from Cal Poly Pomona, their paths will diverge for the first time in their lives. It will be an adjustment for them both.

Karsten has a job lined up as a consultant engineer for the insurance company FM Global. She will work from home and travel for the job as needed.

Kristen -who was also selected to participate in MEP's post-baccalaureate pathways program in partnership with Purdue University- will head to UC Davis in the fall to pursue a master's degree in energy systems.

"People say, 'Maybe you need time apart,'" Kristen said. "But you want to spend as much time with your best friend as possible."