Reinder shared this.
“This window is part of the interior of the Amsterdam Bookshop ‘Pied à Terre’, that specializes in travel books, maps and guides about counties, cities, hiking etc. Cf. https://www.scheltema.nl/piedaterre/
Customers can add a Post-it, and mark the spot they visited. What do you think?
Best regards from the Netherlands”
A new take on crowd sourcing.