Since 2010 Colorado has had one of the strongest growth rates in the country, attracting around 100,000 people each year.

Traffic and housing costs are the popular problems associated with the increase. But there is a third, uglier issue that the city of Denver is trying to change.

Housing types.

“Like who approved that?,” said Larisa Bolivar of the housing complex across from her home on Quitman Street in Denver as she peered out of her bedroom window. “Like who looks at that and says, ‘yeah that looks great.’”

The lot is small. Maybe a sixth of an acre. But it has eight housing units on it, all of them attached to one another in a row that extends perpendicular to the street.

The only part of the units Larisa sees is the side that faces the street. It has nothing more than two square windows placed above a long rectangular window.

“[It looks like] minecraft characters, Lego characters, robots,” Larisa said laughing. “No psychedelics in this house guys.”

It’s hard for Larisa to do anything but laugh at this point. The complex, known as a slot home, has taken the place of the old Victorian-style home that used to be there.

Another slot home is being built only a few lots down.

“We feel like we have no voice against the developers,” she said. “It just takes away from the personality.”

Despite their modern look slot homes aren’t entirely new to Denver, although their construction has certainly ramped up in recent years. They first began peppering the Denver landscape around 2012 as a way to accommodate the city’s growth.

They found their way into Denver neighborhoods as an unintended byproduct of new Denver zoning codes.

Prior to 2010, Denver was built around use-based codes, meaning certain lots were zoned as industrial, residential, commercial, etc. As a way to make neighborhoods more integrated, Denver moved to form-based codes, which allowed for more mixed-use and only required developments fit in a general ‘envelope’ of dimensions.

Slot homes fit in those envelopes.

“[Developers] can usually buy [an old home] for market price, build, and still make a sizeable profit on selling each individual [slot home] unit as a condo,” said Justin Phillips, who is a realtor in Denver. “Yeah, you lose some of the nostalgia and stuff that's here but a lot of these people that have been here [for a long time]. I mean, some of these houses are from the 1920s.”

Justin sees slot homes as a superior product with newer utilities - and it’s true. Slot homes can house nearly 20 people on a lot built for an average family of four.

But for folks on the blocks filled with them, they say the buildings come as an intrusion.

“I’ve closed the curtains in my room since they were built,” Bolivar said.

A builder will typically buy an old home for market price, which averages around $500,000 in Denver. They’ll demolish it for a few more thousand and then build four to eight slot homes for another $500,000 total, which puts the builder about $1 million in debt.

The genius, on their part, is they sell each slot home for the $500,000 price of the original home. Because they’re built vertically slot homes typically have a similar square footage to a normal home. When you do the math a realtor could make out with $3 million in profit if all the homes sell.

The only problem for those who live around them is their out-of-touch look.

“This doesn't look like Denver,” said Christine Franck.

Franck is a researcher at CU Denver, who began researching slot homes after she moved to Denver in 2012 because of how they looked. “Large blank facades that are unarticulated, that don't have openings; they produce a fear response in people," she said. "It creates a real anxiety.”

Here's an example: in 2011 a study by environmental psychologist Colin Ellard found that when strangers were placed in front of a what was deemed a boring building in NYC they had a harder time connecting with one another than when they were placed in an active streetscape full of restaurants and playgrounds.

“We’re not building buildings that are good for our public realm,” Franck said.

And the city of Denver agrees.

Last year the Department of Community Planning and Development created a slot home task force, which has been discussing ways to improve slot homes so they’re more integrated into the neighborhoods in which they’re built.

“It's got to be practical,” said Planning Director Brad Buchanan. “We've got to be able to have the staff resources to accomplish it, but we are absolutely moving in that direction. It's critically important.”

The task force hasn’t created any concrete guidelines yet, but they’ve discussed amending ordinances so slot homes interact with streets more through windows and porches.

They’ve also considered expanding the city’s design review process.

Currently, only about 15 percent of buildings in Denver go through design reviews because they are in historic districts that have strict development and construction standards.

The city doesn’t have a blanket code that requires new buildings to be built in a certain way. It’s why slot homes can sometimes have that “out there” look.

“[Slot homes] can change the experience of a block someone has lived on their entire life,” Buchanan said.

Denver is taking its thinking towards slot homes and applying it to its new master plan known as ‘Denveright.’

The plan would make Denver the first major city in the U.S. to approach planning as a comprehensive process, where different areas play off of one another, instead of a bunch of little plans rolled into one.

The city says it hopes to finish its ‘Denveright’ plan by the middle of 2018.