In the frame
A green sea turtle glides left to right over the edge of a coral reef, its patterned shell and flippers in sharp detail. The reef fills the lower left; the rest is open, deep blue water.
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 turtle's patterned shell and flippers.
- Save for last: the open blue water. About 53% of the frame has little detail, mostly in the top third, and those pieces look alike.
- 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.
- Look-alike tiles are where the numbers help most: plain water or sand gives few clues about order.
- 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: ocean blue (54%), grey (14%), charcoal (14%) and deep blue (8%).
- ocean blue54%
- grey14%
- charcoal14%
- deep blue8%
- slate grey7%
- sky blue3%
How deep it goes
Depth 2 of 5 — an easy dive.
Reef dives sit in the middle: enough pieces to need a plan, never so many that a phone screen feels crowded.