Senegalese painter Omar Ba begins to paint a five-metre-long canvas a deep, dark shade of black. This is how Ba, a rising star in the world of contemporary African art, begins most of his works, which question the state of the world and Africa's place in it. After exhibiting at an array of important galleries and museums around the world, Ba's work is on display in his home country, at the 14th Dakar Biennale, which opened Thursday. IMAGES AND SOUNDBITES ARRANGED IN SEQUENCES