First Light on the Walls

Hard — logic-grid deduction puzzle

Four photographers each took one photo of the mountain fortress at sunrise, but nobody wrote down who stood on which tower, with which camera, or when.

The morning after the mountain fortress joined the World Heritage list, Hana, Woojin, Chaewon and Kyungmin climbed its old walls in the dark, hoping to catch the first light on the stone. Each of them picked a different tower and brought a different kind of camera. Night lanterns were still glowing on just two of the towers, the north tower and the east tower. Then the sun came up over the ridge, and each photographer waited for the perfect moment to take one photo. The four photos were taken at four different times: 10, 20, 30 and 45 minutes after sunrise.

Clues

1. Woojin took a photo later than both Chaewon and Kyungmin.
2. Chaewon's photo came before both Hana's and Kyungmin's.
3. The photo from the video camera was taken after the one from the phone camera and before the one from the film camera.
4. Chaewon took a photo with the phone camera.
5. Kyungmin took a photo after Hana did.
6. Only one of these was true: the drone camera was used on the north tower, or Hana had the phone camera.
7. Woojin stood on one of the two lantern towers, the north tower or the east tower.
8. Either the photo taken 30 minutes after sunrise came from the south tower, or Chaewon stood on the east tower, but not both.
9. If Woojin was on the north tower, then Hana had the drone camera.

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