Four point charges 1μC,-2μC,3μC  and -2μC  are arranged on the four vertices of a square of side 1 cm.  The dipole moment of this charge assembly is

p→=∑qiri→ we can rearrange the charges to form three dipoles with charges as  (-2 and +2) ,(+1 and _1) and (-1 and +1) with first and third in opposite direction and second one is perpendicular to them.