Street artists hired to give authenticity to a Berlin set on Showtime’s Homeland trolled the show by sneaking in Arabic graffiti calling the show “racist,” and even wrote Black Lives Matter.”

TIME reports three artists slipped graffiti critical of the successful show into the October 11 episode, something the show’s producers did not catch during production.

Phrases such as “Homeland is racist,” “There is no Homeland,” and “This show does not represent the views of the artists” were painted into the background of sets, and seen by viewers who could read their messages.

According to Vanity Fair, the artists also wrote “Black Lives Matter.”

Set design artist for the show Homeland wrote that the show is racist in arabic "graffiti". No one noticed. https://t.co/oG0nC4rS7P — hend amry (@LibyaLiberty) October 15, 2015

Heba Amin and Caram Kapp, two members of the Arabian Street Artists, later called Homeland “the most bigoted and racist TV series.”

The show has been criticized for negatively depicting Muslims and the Middle East, according to TIME.

Homeland co-creator Alex Gansa tolf the mag of the artist’s actions, “We wish we’d caught these images before they made it to air.”

Ganda added, “However, as Homeland always strives to be subversive in its own right and a stimulus for conversation, we can’t help but admire this act of artistic sabotage.”

The artists said others on the show were too busy working to create a realistic Syrian refugee camp to pay attention to what they were writing.

“The set decoration had to be completed in two days, for filming on the third,” they said through a statement.

“Set designers were too frantic to pay any attention to us; they were busy constructing a hyper-realistic set that addressed everything from the plastic laundry pins to the frayed edges of outdoor plastic curtains. It looked very Middle Eastern and the summer sun and heat helped heighten that illusion,” they said.

Amin later said the show is “thinly veiled propaganda,” before saying, ”For four seasons, and entering its fifth, Homeland has maintained the dichotomy of the photogenic, mainly white, mostly American protector versus the evil and backwards Muslim threat.”