You could use them as a beginning of the year challenge - give each
student an equal number, have them work on it at home, tell them they
can add 3 or 4 materials of their own and see what creativity
If they won't work on them much at home - do it in school with small
groups. Supply some other found materials for each table (and some
treasures - beads, wire...) they can barter for supplies they want, see
who creates the best idea with their 'natural resources'...