Berlin ? In Katrin Roller’s Berlin apartment, it’s the toilet paper holder that stands out — a homemade contraption of rope and a piece of a rolling pin.

That’s the way her husband wants it. He grew up in the communist-imposed frugality of East Germany, and 20 years after the fall of the Berlin Wall, he still isn’t quite used to the throwaway society. “He thinks you can always use something for something else,” Roller says with a laugh.

Still, it’s a minor point of difference, considering that when they first met 12 years ago, she felt as if they were from different countries. “It was still exotic to bring an eastern German into my circle of friends. I felt like a real pioneer,” she says. “But today it isn’t exotic anymore.”

Marriages like hers are just one of many reasons for Germans to celebrate Monday as they mark the fall of the wall on Nov. 9, 1989.

After “Ossis” and “Wessis” met across the rubble of the barrier that had separated them for decades, their cultural differences gave rise to a German catchphrase: “A wall in the mind,” meaning the vast differences in outlook and living standards between 63 million Germans (Wessis) raised in a free-market democracy and 17 million (Ossis) in a communist dictatorship.

Catrin Schmitt and Yvi Poducek are another couple that has crossed the divide by making small adjustments.

Catrin, the westerner, had to come to terms with knowing that her partner’s uncle worked for the Stasi, the East German secret police. She had to wean her off cheap wine and introduce her to finer vintages. On foreign holidays, when English was required, she had to do the talking because Yvi’s only foreign language was Russian.

Three years ago they entered a legal union and are raising Catrin’s baby daughter and a 3-year-old son fathered by a friend. Yvi has taken Catrin’s surname. This week the son’s fridge magnets spelled “Catrin Loves Yvi.”

“The East and West thing, it’s just not an issue for us anymore,” said Yvi, 37, a hairdresser who owns her own salon. And Catrin, a Web page designer, says: “Now you hardly even hear people referred to as ‘Ossi’ and ‘Wessi.”‘

There are no recent figures on east-west marriages. The last survey, from 1995, said they made up 4 percent of the total, but journalist Simone Schmollack reckons the number is much bigger and always rising.

“It’s becoming always more normal, especially in Berlin, which is a melting pot,” said Schmollack, who wrote a book on relationships across the former divide.

In the early years, the “wall in the mind” was felt everywhere. The Wessis looked down on everything eastern, from the drab clothes and smoky Trabant cars to the communist mindset of leaving everything to the government. The Ossis were repelled by the westerners’ condescension and conspicuous consumption and gap between haves and have-nots.

Today, mixed couples say there is much more that unites them, from ethics and family values to Goethe, Schiller and other German literary greats who were read on both sides of the heavily fenced and mined border.