A US engineering firm whose logo has graced wine bottles and notepaper cubes is stunned to discover its newest potential incarnation – as the national flag of New Zealand.

Images of the logo, used by North Carolina's Peak Engineering since 2008, started circulating on social media last week.

On Saturday, company owners Beth and Jeff Roach said they thought its similarity to "Red Peak", the design that 35,000 people have petitioned to add to the flag referendum, was "curious".

"It's obviously caught us by surprise. . . and we were even more surprised that people had nicknamed it 'red peak'. Obviously we're very flattered!" said Beth Roach.

The couple, from the town of Apex (population 42,000 and recently named the most desirable place to live in America) received an email about the flag debate "from a random New Zealand citizen" on Wednesday.

"I thought it was spam mail and I deleted it," said Beth Roach. More emails followed and the couple were now watching with interest.

Roach said Peak Engineering's name and logo reflected Apex's motto "the peak of good living" and the logo had been used on client gifts, including stationary and wine. She said it wasn't trademarked, but her understanding of copyright was that another company could not use a similar mark.

"I think, ultimately, we would grant a license to anybody willing to use it, and absolutely, the government of New Zealand, not a problem.

"But I think we need to have a conversation with anybody who's interested in using it, just so we clear everything up and make sure it's all above board."

Peak Engineering's logo features a red triangle, a white chevron and two black triangles. Red Peak uses the same elements, but one of the black triangles is coloured blue.

Jeff Roach said he thought it would be "awesome" to see the design on a national flag.

"I think it's a long way from that though. I'm not really sure we've an opinion about what happens if you guys vote in a referendum and that becomes your new flag; what that does for us – I don't think we've thought that far out."

Husband and wife owners of North Carolina's Peak Engineering, Beth and Jeff Roach, had their bespoke logo designed in 2008.

Aaron Dustin, Red Peak's Wellington designer said he'd taken legal advice and there was "absolutely no copyright issue here at all".

Red Peak was one of 18 designs he'd submitted to the flag panel and the only one to make the longlist of 40.

His first reaction was "hope, excitement and uncertainty", but he wasn't surprised he didn't make the final four, announced on September 1. The subsequent groundswell of support for Red Peak was because "it resonates with people", Dustin said.

"They see something that represents their vision for New Zealand as well as respecting our past. Something about it is uniting, and there is a sense of 'bringing us together' that many have mentioned. That doesn't come along often in national symbols."

Artist Dick Frizzell, who has publicly supported Red Peak, said comparing it to similar designs was "a red herring".

"There's a New Zealand roofing company with a similar logo, there's real estate companies with similar logos . . . there are arrows and chevrons, there are road signs telling you not to go over the edge that look like Red Peak.

"Some people say it's ugly and it looks like a Surf Life Saving 'don't swim here' sign. If you're of the mood that you don't want change, you can write a whole essay about how awful it is, and plagiaristic and second hand and everything else – but that's just not the point . . . it's what we imbue it with."

Julie Schmidt, the North Carolina designer who created Peak Engineering's logo seven years ago, said she could see immediate similarities when comparing the two designs as drawings.

"But when I see it as a flag, I feel like it's a different kind of thing.

"I think it's probably safe to say that shapes like triangles or squares lend themselves to certain ways that you would dissect them – I don't know that there's any original ideas anymore . . . with the Internet, we can see lots of images, but if we could really see all the things in the world, there would probably be a 1000 things that looked like that.

"I think if they were an engineering firm in our state, that would be a concern. But a flag in New Zealand? That makes it kind of cool – and again, they could say it's different because there's a blue triangle. I'm all for people putting more good design and more good work out into the world. And if it is enough to make people have a conversation, I think that's a good project."

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