Three A4 sheets of 105g/m2 Tyvek synthetic paper. Made of spun polyethylene fibres, this paper is very strong, tear-proof, waterproof, and nevertheless easy to cut with scissors, a craft knife or a laser, and to sew by hand or machine.
Conventional uses include wrapping for the outsides of buildings during renovation, heavy-duty mailing wrappers and protective clothing. 
We like to sew it, make stencils from it (especially for monoprinting on Gelli plates), paint and print on it.
See more ideas here