Apparently, a “basic math” textbook published by MuangThaiBook Perhaps features a studious porn star in a “school girl’s” outfit on the cover. Perhaps a MuangThaiBook employee thought it would be a good gag.

NY Daily News reports:

Embarrassed Thailand education officials recall thousands of math textbooks after ‘teacher’ on cover revealed to be Japanese porn star

Thai education officials were left redfaced after it emerged that a “teacher” who appears on the cover of a new math book is actually a porn star.

Eagle-eyed college students quickly noticed that the bespectacled educator seductively posing with a folder is, in fact, Japanese XXX-rated actress Mana Aoki.

Publisher MuangThaiBook then confessed to using a screengrab from her “Costume Play Working Girl” movie for the front page of its “Basic Mathematics” textbook.

Some 3,000 copies were sent out to 10 universities before the blunder was noticed.

The textbooks are now all being recalled and will be reissued with a different cover, according to RocketNews24.

It’s not clear, however, how many of the flawed originals will actually be returned.