sentences:  The Vindolanda tablets are made from birch, alder and oak that grew locally, in contrast to stylus tablets, another type of writing tablet used in Roman Britain, which were imported and made from non-native wood.The tablets are 0.25–3 mm thick with a typical size being (the size of a modern postcard).They were scored down the middle and folded to form diptychs with ink writing on the inner faces, the ink being carbon, gum arabic and water.