What started off as an art project became a social media meme and then a civil society movement. A group of women now gathers regularly to cycle in Baghdad and break new ground.
Or is it old ground?
"My mother and my grandmother used to ride bicycles. It used to be normal," Jaber told AFP.
She said she questioned why she had felt so proud when she rode a bike during a visit to London last year.
"It's only a bike. It's a simple thing. It should be normal," the 25-year-old said.
"Does society just not allow us to do certain things or does it start not accepting those certain things because we stopped doing them? That was an important question that had been on my mind for a long time."
To find the answer, Jaber started cycling in her neighbourhood and made that a project for a contemporary arts institute called Tarkib -- an Arabic word which can mean installation and assemblage.
A picture Jaber posted of herself cycling alongside an old man riding his own bicycle and staring at her in reproving disbelief made the rounds on Iraqi social media last year.
"With that old man, I found my answer. For more than five minutes, I was riding next to him and he kept looking at me. He didn't seem to like it," Jaber said.
'I AM SOCIETY'
"Then he stopped looking and went about his business. All the people in the area got used to it, they stopped looking at me... I understood then that I am society. If I want something, I should start doing it."
Jaber instantly became an inspiration for many girls and women across the country yearning to lead their lives the way they choose and not bow to more or less recent social, tribal or religious restrictions.
Hashtags started spreading on the internet and Jaber was overwhelmed by the response she got.
"I received a lot of messages... mostly from young girls. Maybe they needed somebody to stand up for their rights," she said.
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Her red bicycle became the centrepiece of her installation at an exhibit in Baghdad last year and Jaber's action joined a long global history of cycling as a symbol of women's emancipation.
In England, suffragette Alice Hawkins once famously rode down the streets of Leicester to promote women's rights -- scandalously wearing pantaloons.
More than a century later, the symbol is still potent in the Middle East, as exemplified in the 2012 Saudi film "Wadjda" about an 11-year-old girl from Riyadh who defies society and her mother's disallowance by buying the green bike of her dreams with the prize money from winning a Koranic recitation contest.
Jaber's story also echoes that of Bushra al-Fusail, a photographer from Yemen who started her country's first female cycling group in 2015 to affirm women's rights and protest against the war.
In Iraq, women from across the country started posting pictures of themselves on bicycles and dozens have joined group bike rides in the streets of Baghdad, which are closed off to traffic by police who escort the cyclists.
"It's not illegal for a woman to cycle in Iraq but because of the war we Iraqis stopped doing a lot of things we used to do... we are too busy with death," Jaber said.
Jumana Mumtaz, a broadcast journalist from the northern Iraqi city of Mosul, posted a picture of herself on a bicycle from the edge of the battlefield in December to support Jaber's initiative.
"It was a way of challenging ISIS and extremist thought," she said, referring to the Islamic State jihadist group which still controls half of her city despite a three-month-old government offensive.
"Also, a lot of people in Iraq, not just ISIS, think women shouldn't be able to do what they want and think our behaviour is shameful... Marina got many very aggressive comments and so did I," Mumtaz said.
Most of those comments came from men but they are also welcome when Jaber's group organises a ride.
"It's liberating for a man too. Everyone looks so happy, the city even looks more beautiful like this. It feels like the normal life we want," said Mustafa Ahmed, a young army officer, at a recent rally.
"There were some negative reactions at first but the comment I hear the most now is 'Aah, this is the Baghdad we know'," said Jaber, who has received several offers to help distribute free bikes to Iraqi women.
"Now I want to support girls to stop being scared. We can change reality."