There are only so many notes, so occasionally one hit song sounds a lot like another hit song.

In 1982, the Australian rock band Men at Work hit #1 in the U.S. with “Down Under” a song about a proud Australian man traveling the world. It’s also notable for being one of few major hit songs to feature a flute solo. It wasn’t until 2008—more than 25 years after the song’s release—that its writers (Men at Work’s Colin Hay and Ron Strykert) were sued for copyright infringement. After an Australian game show fielded the question “what children’s song is contained in ‘Down Under’?” Larrikin Music received hundreds of emails and phone calls pointing out that indeed, the 1932 song “Kookaburra,” of which the company owned the rights, sounded a lot like the flute solo in “Down Under.” A judge ruled that copyright infringement had occurred, and that going forward 5 percent of royalties for “Down Under” would go to Larrikin. Shortly thereafter, Hay re-recorded the song…changing the melody of the flute solo.
https://www.youtube.com/watch?v=OZzm1C-NlME
In April 2016, a judge ruled that a jury would hear the case of if Led Zeppelin stole the riff of “Stairway to Heaven”—perhaps the most famous riff of the most famous rock song in history. Two years ago, the estate of the deceased Randy Wolfe sued Led Zeppelin’s Robert Plant and Jimmy Page for appropriating the opening melody from “Taurus,” an instrumental song released by Wolfe’s band Spirit in 1968. Never heard of Spirit? They’re pretty obscure, although the suit alleges that Page and Plant could have heard the song because their band shared a bill with Spirit at three music festivals after “Taurus” was released.

In 1994, British rock band Oasis had a hit with “Shakermaker.” It reminded a lot of people of 1971 the Coca-Cola jingle-turned-actual song “I’d Like to Teach the World to Sing.” Among those who noticed a resemblance: the New Seekers, the folk band who actually wrote the song. They sued Oasis for copyright infringement and the parties agreed on a $500,000 settlement. Ever since, Oasis singer Liam Gallagher jokingly inserts lines from “I’d Like to Teach the World to Sing” when he performs “Shakermaker” live.