How to Solve a 4x4 Puzzle Unit

"4x4 unit puzzle" is ambiguous. Please specify the exact puzzle type:

Common 4x4 Puzzles

• 15 Puzzle (Sliding Tiles): 4x4 grid, 15 numbered tiles + 1 empty. Solve by ordering 1–15. Use A* algorithm or pattern databases for optimal solution.
• 4x4 Sudoku (Shidoku): 4x4 grid, digits 1–4, 2x2 subgrids. Standard Sudoku logic.
• KenKen / Calcudoku 4x4: Cages with arithmetic targets.
• Lights Out 4x4: Toggle lights to turn all off. Linear algebra over GF(2).
• 4x4 Magic Square: Fill 1–16 so rows/cols/diagonals sum to 34.
• Nonogram / Picross 4x4: Reveal picture from row/col clues.
• Rubik's Cube 4x4 (Rubik's Revenge): Reduction method → 3x3 stage → parity fixes.

To Get Help

1. Name the puzzle (or source: game, app, book).
2. State the rules/goal.
3. Provide starting state (grid, clues, scramble).

Then I can give a step-by-step solution or strategy.