The sight of shivering asylum seekers queuing for hours outside Berlin's registration centre on a winter's day prompted Van Bo Le-Mentzel to act.
"I fetched my drill and collected some wood that I found randomly in the streets and brought it to the line where people were standing there bored to death and we just started building," the architect said.
The result was small playhouses that children could crawl into for shelter, and also the birth of the Tiny House University, a project bringing together architects, designers and refugees to find new ways to house a population in need.
"We are trying to create new kinds of housing forms in society in which it's possible to live and survive without having land or money," said Mr Le-Mentzel.
The tiny house trend emerged several years ago, largely in the United States as people chose to downsize their living space out of environmental or financial concerns.
In Berlin, it has been given a twist for contemporary needs.
For a start, Mr Le-Mentzel's team, which includes six refugees, is collaborating with Berlin's Bauhaus-Archiv museum to build 20 tiny houses occupying 10 square metres each.
Read more: Arab Street in Berlin brings nostalgia for Syrian refugees
The houses will form a temporary village that will be on exhibition until next March.
Some will serve as lodging, others as a library, cafe, workshop or community centre.
Each building is fitted with wheels, which means they can be parked on public streets like a trailer, Mr Le-Mentzel said.
"In Berlin we have 1.5 million cars registered and they are all standing in the streets overnight, not in use. Each car is about 10 square metres," he said.
"So I'm asking what would happen if we just replace these 1.5 million cars with tiny houses or with mobile playgrounds for kids or with open spaces where neighbours can cook together, eat together, find company together, where refugees can create a start-up in the streets — opening a restaurant, [giving] a haircut."
Property prices in Berlin shot up as the city shed its Cold War divided past to become a tourism and party hot spot, as well as an investment magnet.
Although new builds are mushrooming across the capital, refugees and low-income locals are finding themselves priced out.
Mr Le-Mentzel sees Tiny 100 as a prototype for small apartments which can be let out for €100 (Dh433) a month to low earners.
His ultimate goal is to fit out a building not only with regular-sized apartments, but also such compact homes, allowing the "rich and poor, students and entrepreneurs" to live together.
"It will be a house that mirrors society," he said, adding that talks are being held with "three or four investors" about making his dream come true.
"But we are at the beginning of the process."
Ali Fadi, a Kurdish refugee from Syria, has not thought as far as owning a tiny apartment.
The 33-year-old is an experienced carpenter who is simply revelling in being able to practise his trade after being shut out of the German job market because he lacks formal qualifications.
"I hope I can get a job doing this," Mr Fadi said as he measured a piece of wood for a tiny cafe.
At a warehouse area in southern Berlin, another member of the team, Noam Goldstein, is fitting insulation into one of the 20 tiny houses.
His version of the small home includes solar panels, a compost toilet and a hydroponics garden.
The carpenter expects materials for the house to cost between €12,000 and €15,000.
While some components like windows have to be purchased, much of the wood used is recycled pallet wood.
"When you look at the financial aspect, it provides a very cheap way for people to build their own house," Mr Goldstein said.
Researcher Amelie Salameh, who tested the first of the 20 tiny houses, is a convert.
Built by Mr Le-Mentzel himself, the six-square-metre unit was self-contained, with a living room, kitchen, sleeping area, toilet and shower.
"The way it was designed, there were mirrors, a lot of light, I never felt trapped inside," said Ms Salameh, who lived in the house called Tiny 100 for three weeks.
She even had two friends sleep over for a night, and once also hosted 13 people.
"It was fun," she said. "You just have to think about where you're putting your stuff, and to tidy up constantly, because the place gets full quickly."
