Assertion: code wheel | /r/MadeOf | two circular sheets
Facets:
value: with the back sheet
type: OTHER
value: with challenge symbols
type: OTHER
Source sentences:
text: A simple 2-ply code wheel consisted of two circular sheets, both with challenge symbols printed at intervals around the rim, and with the back sheet containing a table of responses printed to fit to the circle, and the front sheet a series of holes allowing the responses to be viewed, each hole labelled with a challenge symbol.