"four double-sided sheets of wax"

Wax Tablet and Stylus, detail from a red figure vase
Creative Commons Attribution Share AlikeWax Tablet and Stylus, detail from a red figure vase - Credit: Pottery Fan/Wikimedia Commons
Romans used wax tablets for writing, using a stylus to make marks in the soft wax. These notes could be erased easily by rubbing over and smoothing out the wax. More permanent writing could be committed to sheets of papyrus, paper made from the reeds of the papyrus plant.

Papyrus Plant, Syracuse
Public DomainPapyrus Plant, Syracuse - Credit: Gun Powder Ma/Wikimedia Commons