When does the Daily Logic Puzzle reset?

A brand new official daily challenge generates automatically at 00:00 UTC (midnight Coordinated Universal Time) every day. Everyone around the world receives the exact same daily puzzle seed.

How do consecutive daily streaks work in Daily Logic?

Completing the official daily puzzle on consecutive UTC calendar days increases your active streak by 1. Missing a calendar day resets your active streak to 1 upon your next successful puzzle completion.

Can I practise without affecting my official daily streak?

Yes. Practice Mode generates unlimited randomised 4×4 puzzles and records your personal practice bests without modifying your official daily streak or status.

What is the mathematical definition of a Latin Square?

An n x n Latin square is an algebraic matrix filled with n distinct symbols such that each symbol occurs exactly once in each row and exactly once in each column.

What keyboard shortcuts can I use while solving?

You can select symbols using keys 1 (Sun), 2 (Moon), 3 (Star), 4 (Comet), clear cells with 0 or Backspace, and undo moves with U or Cmd/Ctrl+Z.

Daily Logic Puzzle

Today

Fill the 4×4 grid so each row and column contains exactly one Sun (☀️), Moon (🌙), Star (⭐), and Comet (☄️).

Current streak: 🔥 0 | Max: 0

Select a mode and press Start Puzzle to begin the Daily Logic Challenge.

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How to play

The objective is to fill the 4×4 grid with 4 celestial symbols: Sun (☀️), Moon (🌙), Star (⭐), and Comet (☄️).

Rules:

Every row must contain all 4 symbols exactly once.
Every column must contain all 4 symbols exactly once.
No duplicate symbols are permitted in any row or column.

Controls:

Click/tap any cell to cycle through the symbols.
Or select a symbol from the palette and click cells to place it.
Use keys [1-4] to place symbols, [0] or [Backspace] to clear, and [U] to undo.

A brand new official daily challenge is generated automatically at midnight UTC every day.

Step-by-Step Solving Guide

Inspect the Initial Grid
Look at the pre-filled celestial symbols (Sun, Moon, Star, Comet) fixed onto the 4x4 matrix.
Find Forced Rows and Columns
Locate any row or column with 3 existing symbols. By Latin square rules, the remaining empty cell must contain the missing fourth symbol.
Apply Intersection Elimination
When placing a symbol, verify that neither its row nor its column already contains that glyph.
Complete the Celestial Grid
Fill all 16 cells correctly. Upon placing the final valid symbol, the puzzle completes and your streak is updated.

Celestial Latin Square Combinatorics

Daily Logic Puzzle is based on mathematical Latin squares (the theoretical foundation of Sudoku):

Order-4 Matrix: A 4×4 grid contains 16 cells requiring 4 distinct celestial glyphs (Sun, Moon, Star, Comet). There are 576 possible reduced and transformed 4×4 Latin squares.
Orthogonality Invariant: Each symbol must appear exactly once in each horizontal row and vertical column with zero row/column collisions.
Deterministic UTC Seeding: Daily puzzles are mathematically seeded by UTC date strings (e.g. YYYY-MM-DD), ensuring reproducible, single-solution solvability for all global players.

Deduction & Elimination Strategies

Solve any Daily Logic puzzle using systematic logical deduction:

Cross-Hatching: Scan rows and columns containing 3 known symbols; the remaining empty cell is uniquely forced.
Intersection Elimination: If a symbol already exists in row 2 and column 3, that symbol cannot be placed at cell (2, 3).
Non-Destructive Undo: Use the undo button or keyboard shortcut U to explore potential placements safely.

Frequently Asked Questions

When does the Daily Logic Puzzle reset?: A brand new official daily challenge generates automatically at 00:00 UTC (midnight Coordinated Universal Time) every day. Everyone around the world receives the exact same daily puzzle seed.
How do consecutive daily streaks work in Daily Logic?: Completing the official daily puzzle on consecutive UTC calendar days increases your active streak by 1. Missing a calendar day resets your active streak to 1 upon your next successful puzzle completion.
Can I practise without affecting my official daily streak?: Yes. Practice Mode generates unlimited randomised 4×4 puzzles and records your personal practice bests without modifying your official daily streak or status.
What is the mathematical definition of a Latin Square?: An n x n Latin square is an algebraic matrix filled with n distinct symbols such that each symbol occurs exactly once in each row and exactly once in each column.
What keyboard shortcuts can I use while solving?: You can select symbols using keys 1 (Sun), 2 (Moon), 3 (Star), 4 (Comet), clear cells with 0 or Backspace, and undo moves with U or Cmd/Ctrl+Z.

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