To colour a region in Venn Diagram, say the middle one in violet formed by the arcs [b]k[/b], [b]s[/b] and [b]r[/b], we use the following three commands:[br][b]G = Point({k, s, r})[br]G' = G[br]loc1 = Locus(G', G)[/b][br]The region [b]loc1[/b] formed by arcs [b]k[/b], [b]s[/b] and [b]r[/b] is then created and we can now colour it.