Jigsaw puzzles have been trending as people seek out indoor activities to occupy their time during lockdowns caused by the coronavirus pandemic. And big brands have taken notice. Heinz and McDonald’s both recently came out with separate promotions involving custom puzzle giveaways.

In recent weeks, sales of jigsaw puzzles have gone way up. Puzzle maker Ravensburger reported that its sales were up 370% year-over-year in March and April. Jiggy, a millennial-focused direct-to-consumer puzzle company that features the work of female artists, has also experienced an uptick in sales.

“The demand increase was pretty much like clockwork, especially in New York,” Jiggy founder and CEO Kaylin Marcotte told Refinery 29. “The weekend of March 14-15 when people really started taking it seriously and staying home, almost immediately traffic, sales, social engagement, everything started going up.”

Jigsaw puzzles are a welcome distraction and perhaps even a way to reduce anxiety, so it’s no wonder that they, like adult coloring books, are seeing a surge during the pandemic. Custom jigsaw puzzles also make great promotional items.

McDonald’s in Belgium recently created a 500-piece burger puzzle that shows off the fast-food giant’s signature item once completed. The chain was giving away 20 sets of the puzzle via an Instagram contest.

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Huge fan of McDo and - since the lockdown - puzzling 🧩? Well, we have something for you! 20 Yummy Burger Puzzles to give away. 🍔 1. Share this post in your Story 2. Tell us in your Story why you want it. Be creative. 3. Tag @mcdonaldsbelgium We’ll pick the winners on 27/4!🍀 Contest rules via link in bio. • • • #McDo #BurgerPuzzle #Yummy #Lockdown #puzzling

A post shared by McDonald’s Belgium (@mcdonaldsbelgium) on Apr 24, 2020 at 8:33am PDT

Heinz Ketchup decided to go the more challenging – but amusingly on-brand – route, releasing a 570-piece puzzle, with each piece hued in identical Heinz red. The brand, which is giving away 57 of the all-red puzzles in 17 countries, jokes that it may just be the world’s slowest puzzle.

This might be the slowest puzzle on earth. 570 pieces. All Heinz red. Tell us who you wish you could finish this with. pic.twitter.com/jKrcauLH0e

— Heinz Ketchup (@HeinzKetchup_US) May 5, 2020

“Heinz is known for its iconic, slow-pouring ketchup,” said Brian Neumann, senior brand manager of Kraft Heinz Canada, in a press release. “In a period when everyone has a little more time on their hands and puzzle popularity has skyrocketed, we wanted to help pass the time by connecting the two.”