Though he’s only 8, Vance Arnold has already assembled at least 60 Lego sets of all sizes. “The biggest box was the crane,” he said, describing the kit for the motorized crane, which contained 3,800 pieces.

Vance was in his happy place on Saturday as he and schoolmate Braden Callihan, 9, spent the day at BrickUniverse, a convention for Lego fans being held at the Pontchartrain Center in Kenner.

Organizers said the convention was the first such Lego gathering in the state. Demand for tickets was high. The 4,000 total Saturday-Sunday tickets sold out on Friday, before doors had even opened. On Saturday morning, parents who had hoped to purchase tickets at the door left with crying children in tow.

Inside the Pontchartrain Center, parents who had wisely purchased tickets in advance held small children on their shoulders and pushed strollers.

In a centrally located booth, one Louisiana artist, a veteran, displayed large facial portraits that she has created using Legos to relieve post-traumatic stress disorder.

In one corner, Lego artists had created a small Carnival street scene of New Orleans, complete with viewers on balconies and royalty standing on floats.

On some nearby tables, children built cooperatively; at others, they competed. Vendors showed off Lego artwork or sold handmade crafts such as Lego fidget spinners and hair ties.

Vance said he was inspired by the creativity in the New Orleans scene. When he plays with Legos at home in Port Allen, he sometimes uses his imagination and canisters of extra parts to make new creations. But typically, he and his father, Clyde Arnold, 51, simply follow each set’s prescribed directions, after using paper plates to group the classic plastic bricks, tiles and pins by type.

Creating the crane required 35 paper plates for sorting and 18 hours of assembly spread over about four days, he said, noting that assembling each kit has highs and lows.

“Sometimes, I feel very calm. Sometimes, I feel a little stressed because I have no clue what to do next,” he said.

Behind him, Lego artist Robin Krauth, 46, nodded from her artist’s booth. Front and center was a large, heavily purple image of two feline eyes, an LSU tiger. It was a fitting creation for Krauth, the only Louisiana artist to display in this weekend’s convention.

Krauth, a native of Zachary who now lives in Walker, came to the world of Legos several years ago, after returning home from a tour as a U.S. Army medic during the Iraq War. There, she suffered debilitating injuries to her knees and hips that left her wheelchair-bound.

Like other medics she served with, she also returned with severe PTSD. “We saw too much,” she said.

That’s where Legos came in. Her husband, a fellow soldier whom she met in Baghdad, gave her the first set, a 1,228-piece Harry Potter castle, while she was living at an Army base in Tacoma, Washington. She soon joined a local Lego club and began to see the artistry in the small blocks.

She now creates artwork, mostly pixelated facial portraits, using Legos that she orders by the thousands from an online Lego market called BrickLink.

She and her mother, Kathaleena Krauth, recalled how Robin’s father, William “Bud” Krauth, a U.S. Marine who served in the Vietnam War, would hole up in their backyard shed building small toys, likely because of undiagnosed PTSD.

Today, crafts are seen as “recreational therapy” and are often part of formal treatment plans for PTSD.

Robin Krauth smiled as a pair of children skipped past her Saturday, headed toward a Lego construction booth. The little bricks have the same effect on her, she said. “My anxiety goes down and my concentration goes up. I feel happy, peaceful,” she said.