Noggin is a shelf of short daily puzzles. Every day the same four games are set for everybody, you play each one once, and the whole day adds up to a single score out of 400 you can compare with a friend.

THE DAILY LINE-UP

• Spectrum: six things and one hidden scale. Put them in order. It rewards knowing roughly how big, old or hot things are, and forgives you for not knowing exactly.

• Rung: climb from one word to another, changing a single letter at a time, every step a real word. You can always get there. The question is how directly.

• Vault: a hidden code and nine guesses. Every guess comes back with how many symbols are exactly right, how many are one slot off, and how many are further away. It never says which.

• Deduce: a logic grid. Four people, three things to work out about each, and clues that rule things out rather than hand you answers. Exactly one arrangement fits, and you never have to guess.

MORE BRAIN TEASERS

Beside the four sits a second shelf: games set every day and scored out of 100, but never counted in the day's total. A Sudoku that never needs a guess, a five-by-five crossword, a themed word search where the letters fall, and more.

HOW IT WORKS

• One puzzle per game per day, the same for everyone.
• Every game is worth up to 100. Running out of checks is not zero. You score for what you got right.
• Everything you need is on the screen. No guessing required.
• Your streak counts days you played anything.
• Play forever without signing up. Sign in with your email if you want your scores on more than one device.
• Share a score without spoiling the puzzle.
• A daily reminder, if you want one.

Made by Graevyn Games, a one-person independent studio. If a puzzle seems wrong or a word should have been accepted, the feedback link is in the menu, and it gets read.