Author 'Spiros' (Original: Perronnet Catherine) : A mount that takes up two photos of Perronnet Catherine (see original photo and photo-related) with trees in the process of digesting a metal plate.
We can organize a competition to determine the time elapsed between the position of the left and right. Catherine will, I hope, to take photos regularly to provide participants with additional information. The results will be announced in several years.
Golondrina, great organizer of the contest of any kind, will select and distribute the awards.