In the frame
At low tide, rounded rocks covered in dark blue mussels and pale barnacles shine wet in the light. Brown seaweed hangs over them, and channels of seawater run between the rocks.
This dive turns the picture into a 4 × 4 slide puzzle: 15 tiles and one empty space. The shuffle is fixed, so everyone starts from the same board, and it is always solvable.
Dive plan
- Start with the easy part: the channels of water between the rocks.
- Almost every part of this frame has detail. The least distinct part is the repeating mussel texture, and even that has texture to go on.
- Finish the top row first, then the left column; the puzzle shrinks to a smaller board each time.
- Switch on the numbers if two tiles look alike — they show where each tile belongs.
- The picture is busy enough that neighbouring tiles can usually be told apart without numbers.
- On a 4 × 4 board, leave finished rows alone and work only in the rest of the board.
Colours of the picture
Main colours, measured from the picture's pixels: charcoal (50%), grey (26%), slate grey (14%) and brown (10%).
- charcoal50%
- grey26%
- slate grey14%
- brown10%
How deep it goes
Depth 1 of 5 — a calm paddle.
Reef dives sit in the middle: enough pieces to need a plan, never so many that a phone screen feels crowded.