Hong Kong student protesters practice use of petrol bombs, bows and arrows Student protesters at Hong Kong's Polytechnic University practice how to use Molotov cocktails and bows and arrows, as worsening violence rocks the city. Universities have become the epicentre of battle, with students -- joined by other black-clad 'braves' of the frontline protest movement -- saying they have been pressed into the defence of their campuses by police threats. IMAGES AND SOUNDBITES