A 91-year-old woman is under investigation in Germany after filling in blank spaces on a crossword-themed artwork in a museum.
"Reading-work-piece" is a 1965 piece by avant garde artist Arthur Koepcke and features the phrase "insert words".
The woman began writing on it using a ballpoint pen during a visit by senior citizens to Nuremberg's Neues Museum.
Museum officials say they believe the work can be restored and said the woman was reported for insurance reasons.
The woman is being investigated for damage to property, although there is no suggestion of any malicious intent.
The pensioner told police she understood the English-language instruction on the artwork to insert words and took it as an invitation to fill in answers to the clues, Suddeutsche Zeitung reported.
She added that this should not have come as a surprise to the museum as it had not put up a notice instructing visitors not to write on the piece, the newspaper said.
Gerlinde Knopp, who was leading the excursion, said the museum was also full of interactive art, making it easy to lose sight of what one could and could not do there,
"Reading-work-piece", which is on loan to the museum from a private collection, is insured for €80,000 ($89,000; £67,000).