So I organized a sketch sequence for them, the same exercise I give to my architecture students.
5 stages: they start in the street and make a sketch about what they observe. Then to a porch, the same thing. Then into an atrium, followed by a facade, and the last impression must be drawing of a rough stone in that facade. All max 20 minutes, that's hard work.
Next to giving instructions I managed to make a few sketches of my own, see above.