An art installation by Ai Weiwei is unveiled at Harbour Green Park in Vancouver recently. The work is horizontal and called F Grass. Made by cast iron and cover 13.5 square meters and comprised of hundreds of metal blades of grass arranged in a calligraphic “F”. They resemble traffic spikes used by police to stop wheeled vehicles. The “F” is short for the F-bomb in english and in Mandarin, the word grass sounds almost identical to the f-word. With such symbolism Ai Weiwei is again sending another message as a defiant gesture against the authorities that keeps him under surveillance.