A Viewgraph

A <a href="https://en.m.wiktionary.org/wiki/graph" title="graph" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">graph</a> (or similar <a href="https://en.m.wiktionary.org/wiki/chart" title="chart" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">chart</a>) produced as a <a href="https://en.m.wiktionary.org/wiki/transparency" title="transparency" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">transparency</a> for use with an <a href="https://en.m.wiktionary.org/wiki/overhead_projector" title="overhead projector" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; background: none rgb(255, 255, 255); color: rgb(107, 75, 161); hyphens: none;">overhead projector</a>.