Consider point group 4mm. Sketch the arrangement of symmetry elements in the group and a representative pattern of objects that con- forms to this symmetry.

(b) For values of n from 1 to 6. Use the stereographic projection (open and filled circles) to show patterns representing ̄n. Decompose each of the patterns into combinations of simpler one-step operations where possible, For example, ̄3 = 3 + ̄1. Which rotoinversion or roto-reflection axes cannot be decomposed?