The scene
Photography Studio · Colour testsSomeone has replaced the winning photograph in a competition. The camera recorded their pass through a mirror, and the monitor saved the image rotated.
The three passes have different markings. A dot and a dash can identify the pass once you recover its original orientation.
What we know for certain
One of these people made the swap using their own pass. There were no loans or forgeries. The image underwent exactly the two operations described, in that order. The marks did not change during the competition.
The three accounts
Santi Cano
Printer«My pass has the dot at the top left.»
Tània Sol
Curator«My card also has a dash on the right.»
Uri Sala
Installer«All the marks on my card were intact.»
Examine the evidence
0 of 5 openedOpening these five clues does not cost points.
01The original passes
With the text upright, Santi has a dot at the top left and a dash at the bottom right. Tània: a dot at the top right and a dash at the bottom right. Uri: a dot at the bottom left and a dash at the top right.
02The first operation
The mirror swapped left and right; it did not swap top and bottom. This is the only reversal produced by the mirror.
03The second operation
The monitor then rotated the image by half a turn. That rotation swapped top with bottom and left with right.
04The saved image
The final image has a dot at the bottom left and a dash at the top right, with no additional marks.
05One pass per person
The checkpoint verified all three passes and their holders. Nobody exchanged them.