Three neon pink seesaws transformed the border fence between the United States and Mexico last Sunday, giving families on both sides the chance to play together.

Two architecture professors have taken a new step in reenvisioning the fraught concept of the border wall as a method of connection. Ronald Rael and Virginia San Fratello conceptualized the ‘Teeter-Totter Wall’ years earlier, but the art installation was brought to life over the weekend “in an event filled with joy, excitement, and togetherness,” according to Rael’s Instagram.

The seesaws were brought to Sunland Park, N.M., and fed through the narrow gaps in the tall metal border fence that separates it from Ciudad Juárez, Mexico. Half of each seesaw was on the American side, and half was on the Mexican side.

This means that the only way for anyone to enjoy the seesaw is for both sides to work together—a person sitting on the American side of the seesaw can only be propelled up into the air if someone on the Mexican side puts their weight on their end of the seesaw.

“The wall became a literal fulcrum for U.S. – Mexico relations and children and adults were connected in meaningful ways on both sides with the recognition that the actions that take place on one side have a direct consequence on the other side,” said Rael in an Instagram post celebrating the art installation.

Pictures and video of the installation show children and adults on both sides smiling and laughing as they teeter-tottered together.

San Fratello posted photos on her own Instagram of people using the seesaws, captioning each with words such as “happiness,” “togetherness,” and “joy.”

The seesaws were a temporary installation, and have since been taken down.

The idea started as a drawing published in Rael’s book, “Borderwall as Architecture: A Manifesto for the U.S. – Mexico Boundary,” which grapples with how to conceive of architectural and artistic ideas that could transform the controversial and emotionally fraught border wall.

Rael is an associate professor of architecture at the University of California, Berkeley. San Fratello, his architectural partner, is an assistant professor at San Jose State University. They got help making the seesaw a reality from the CHOPEkE collective, a Mexican organization that builds housing projects.

Walls or fencing covered about one-third of the 3,145 km-long border between the two countries as of January. U.S. President Donald Trump aims to expand that as part of his battle against asylum seekers.