Could artificial intelligence (AI) write sonnets as good as the Bard? A poetry writing algorithm developed by scientists was able to fool people trying to distinguish between human- and bot-written verses nearly 50 per cent of the time. However, experts could still easily identify machine-generated poetry, and AI may have a long way to go before it can outdo Shakespeare, researchers said. Computer scientists at University of Melbourne in Australia and University of Toronto in Canada designed an algorithm that writes poetry following the rules of rhyme and metre.

In some ways, the computer's verses were better than Shakespeare's. The rhymes and metre in the machine-generated poetry were more precise than in human-written poems. The best version of the algorithm fooled people nearly 50 per cent of the time. However "Deep-speare" still has a long way to go before it writes anything worthy of the Western canon, researchers said. "It's very easy for me to tell what's by a computer or not ridiculously easy," said Adam Hammond, an assistant professor at University of Toronto.

"We solved two out of four problems," Hammond says, referring to rhyme and metre. "The other two are much harder: making something that's readable and something that can evoke emotion in a reader," he said. Researchers trained a neural network using nearly 2,700 sonnets from a free digital library. The computer uses three models - language, metre and rhyming - and probability to pick the right words for its poem. It produced quatrains, or four lines of verse, in iambic pentameter.

The researchers assessed their results by asking people online to tell the human and algorithm poetry apart. Most laymen could not tell that verses like this one were the work of a programmed poet: "With joyous gambols gay and still array/ No longer when he twas, while in his day/ At first to pass in all delightful ways/ Around him, charming and of all his days." However, Deep-speare didn't fool the expert. Hammond said it was easy to spot the computer's verses because they were often incoherent and contained grammatical errors like the one above: "he twas." As further comfort to poets who worry about being replaced by AI, Hammond said there is much more to a sonnet that a computer can not imitate yet.

Researchers want to fine-tune the algorithm so that it sticks to a single topic, or design an algorithm that can write short fiction. "Our results suggest that future research should look beyond metre and focus on improving readability," they said.