This post is superseded. An earlier draft incorrectly framed a country-choice choropleth on an Eiffel Tower photo as the main Clef “world map” experiment.
The intended experiment is the blind-Earth land/water grid (Henry / outsidetext recipe) with System One choice questions for Clef, Clef-flash, and Jev:
→ Blind Earth with Clef, Clef-flash, and Jev
How-to + maps: dylanler/blind-earth-clef-jev.