We are grateful to the anonymous reviewers
for their comments and suggestions; Jr-Iang Chiou for generating
the results; all the participants of the user study for their time
of scanning QR codes; and Gerardo Figueroa for video narration.
We are thankful to Luis Sousa for granting permission to use the
panda photo. The Cat and Arc de Triomphe are image courtesy of
David Corby and Benh LIEU SONG, respectively. The project was
supported in part by the National Science Council of Taiwan (NSC-
102-2221-E-007-055-MY3 and NSC-102-2220-E-007-023), Ministry
of Economic Affairs of Taiwan (MOEA-102-EC-17-A-02-S1-
202), an Adobe research gift and an UCL impact award.