As partners in life and work, the architects Tom Morbitzer and Goil Amornvivat have faced many challenges together. But every December, the founders of the New York-based firm Ammor Architecture find themselves mulling over one question: How should they decorate for the holidays?

Mr. Morbitzer, 51, grew up in Columbus, Ohio, in a family that always went all-out. “Christmas was a very big deal,” he said, noting that his grandparents and parents, who have a German background, stopped at nothing to create a festive atmosphere.

“We’re talking the full tree, house decoration, cookies, everything,” Mr. Morbitzer said. “It was constant parties, music and fun.”

Mr. Amornvivat was born in Bangkok, where his family observed Buddhist holidays. There was nothing like the monthlong marathon of tree-trimming and caroling Mr. Morbitzer engaged in every December.

Rather than ignoring that difference when decorating their 750-square-foot, one-bedroom apartment in Williamsburg, Brooklyn, they decided to put their own spin on holiday traditions by freely borrowing elements from both of their cultural backgrounds.

“We have tried to come up with ways to decorate and celebrate that bring together the memories and festivities Tom holds dear while leaving room for new interpretations we both enjoy,” said Mr. Amornvivat, 53. “Our image of Christmas had to be inclusive.”

To create decorations up to the task, the couple turned to the skills they know best: drawing, painting and model making.

A Tiny Work of Architecture

Since 2014, Mr. Morbitzer and Mr. Amornvivat have crafted an annual custom holiday ornament they call an “Ammor-nament,” which they produce in multiples to give to friends and clients. Made from a single sheet of folded, laser-cut metal, it always takes the shape of a house but is detailed in a way that playfully riffs on the upcoming year’s Chinese zodiac animal.

For the year of the rat, for instance, they designed an ornament inspired by “Hickory Dickory Dock,” with a mouse in a clock featuring numerals from different cultures.

This year, for the year of the horse, they designed an ornament that is a play on Greek mythology, with a classical temple meant to represent democracy and Perseus flying in on Pegasus to save the building from an attacking sea monster.

“Read into it what you will,” Mr. Morbitzer said with a laugh.

A Cross-Cultural Tree

To decorate their tree, the couple hang ornaments that spark memories old and new.

There is a tiny red stocking filled with 51 pennies, a tradition Mr. Morbitzer’s parents began when he was a newborn by adding one penny to the stocking every year. There is also a tiny glass pickle that evokes another family tradition with German roots: When Mr. Morbitzer was a child, whoever could find the pickle on the tree received a small gift.

For color, there is checkered ribbon made from pha khao ma, a multipurpose textile Mr. Amornvivat purchased in Thailand.

Recent additions to the tree include ornaments depicting French bulldogs, which are tributes to their former pets, Marly and Lil Lily Munster.

A Creative Window Display

Many people decorate windows with candles, wreaths and garlands during the holidays, but for the couple’s apartment, Mr. Amornvivat wanted to do something different. To enhance the window looking out to their balcony, he created a large-scale frame from two layers of foam board. Using a utility knife, he cut the first layer of the board with patterns resembling geometric tree branches. For the second layer, he added the shape of a gable roof. In between them on the ceiling, he installed an LED tape light, which came with a remote control that adjusts the brightness and color of the light.

Now, the living room “feels like the inside an Ammor-nament,” Mr. Amornvivat said. But it is also meant to be a contemporary reinvention of a German schwibbogen, a traditional arched candleholder that often features backlit two-dimensional scenes.

Leveling-up the Holiday Buffet

Most years, Mr. Morbitzer and Mr. Amornvivat approach holiday decorating as a chance to get together with friends. They put out a buffet of treats on their kitchen island and invite their guests to graze as they help decorate the tree.

To make the buffet look impressive, they elevate plates on stands they designed and made with a 3D printer. “It’s like building an architectural city of food tiers,” Mr. Amornvivat said, “which is exciting to me.”

This year, they stocked the plates with snacks like cheese and crackers, as well as more personal bites.

“The pigs in a blanket are a cheeky nod to the food of my past,” Mr. Morbitzer said.

Mr. Amornvivat added skewered cubes of a pandan-flavored Thai layer cake and golden balls of thong yot, a traditional Thai dessert that represents a blessing of wealth, from the restaurant SriPraPhai.

Do-It-Yourself Decorations

Rather than buying a wreath made from greenery to hang on their front door, the couple made one of their own from paper. The piece is crafted from overlapping rings of white, black, silver and gold paper, which they cut with the shapes of trees, stars, reindeer and people holding hands. It was produced with the help of a laser cutter and pasted together, creating an intricate composition that encourages arriving guests to stop for a closer look.

But a laser cutter isn’t required to make intriguing paper decorations. Inside the apartment, Mr. Morbitzer painted watercolor pictures of candy canes, which he cut out by hand and taped to baker’s twine to create a colorful garland.

Mr. Amornvivat, meanwhile, cut silhouettes of city skylines from leftover squares of watercolor paper with his utility knife. After folding the base of each paper to make the silhouettes stand up, he placed an LED votive candle behind them to add a glow in the windows.

“We met in graduate school when we were making things, and that’s still how we connect,” Mr. Amornvivat said. That’s why he and Mr. Morbitzer continue to find joy in putting their own twist on holiday decorations, he added: “We’re making new traditions together.”