Daily Brains · one diamond of digits a day, gentle Monday to fiendish Sunday.
Diamond Mindbender is the number-logic puzzle in Daily Brains (/daily). Each day sets one diamond-shaped grid (rows 1, 2, 3 … up to the widest row and back down). Every cell holds a digit 1–9 and is tied to its neighbours by the day's rules; a few cells are given and the rest must be deduced. Every diamond is generated from the puzzle number and proven by a solver to have exactly one solution, so everyone in the world cuts the same stone on the same day.
STORY & LORE
Crown, girdle and pavilion
The grid is named like a cut gem. The widest row is the girdle. Rows above it are the crown, where each cell is computed from the two cells touching its lower edges. Rows below it are the pavilion, where each cell is computed from the two cells touching its upper edges (or, on some days, has no arithmetic rule at all).
Gems
A ruby ◆ on a cell means the digit there is prime (2, 3, 5 or 7). A sapphire ◇ means it is even (2, 4, 6 or 8). Gems are never placed on given cells, so each one is a real clue.
How a diamond is made
The generator builds a random complete diamond that obeys the day's rules, places the gems, then removes given digits one at a time, keeping a removal only if a backtracking solver still finds exactly one solution. On the hard days it builds several candidates and keeps the one the solver finds hardest. Easy days stop removing clues early so they stay generous.
HOW IT PLAYS
The rules
Crown, sum: add the two cells below; if the total is over 9, take 9 off (so 7 and 5 make 3). Crown, gap: the difference between the two cells below (so they can never be equal). Pavilion, product: the last digit of the two cells above multiplied (never 0, so a 5 can never sit next to an even digit there). Pavilion, free: no arithmetic. No repeats: no digit appears twice along any diagonal line of the whole diamond.
Playing
Tap a cell, then a digit. Pencil mode jots candidates in a small 3×3 grid. Cells that break a rule (a crown or pavilion sum that does not add up, a repeat on a diagonal, a gem holding the wrong kind of digit) turn red automatically. When a row is full and breaks no rule it lights up like a polished facet; when the whole diamond obeys every rule it is solved. Check marks every filled digit that differs from the solution but costs 75 points. Give up reveals the diamond and ends the day as a loss. Keyboard: 1–9, arrows, P for pencil, Shift+digit for a single pencil mark, Backspace to erase, Z to undo.
Scoring
A solve scores 600 plus a speed bonus of up to 400: the full bonus inside the day's par time, fading to nothing at three times par. Each check costs 75. The minimum for a solve is 100 and the maximum is 1000. Solving without a check is a perfect day.
Sharing
The share card draws the diamond in emoji without giving away any digit: 🔷 for given cells, 💎 for cells you cut, 🔶 for cells a check caught wrong, and 🪨 for cells left uncut if you gave up.
THE WEEK
| Day | Level | Width (cells) | Crown | Pavilion | No repeats | Given digits | Par |
|---|---|---|---|---|---|---|---|
| Monday | Gentle | 3 (9) | Sum | Product | — | 5 | 3 min |
| Tuesday | Steady | 4 (16) | Sum | Product | — | 7 | 5 min |
| Wednesday | Tricky | 4 (16) | Sum | Free | Yes | 6–10 | 7 min |
| Thursday | Twisted | 5 (25) | Gap | Product | — | 6–7 | 10 min |
| Friday | Tough | 5 (25) | Gap | Free | Yes | 8–12 | 13 min |
| Saturday | Brutal | 6 (36) | Sum | Free | Yes | 10–16 | 16 min |
| Sunday | Fiendish | 6 (36) | Gap | Product | — | 4–7 | 20 min |
REWARDS
| Event | Reward |
|---|---|
| Solve the day's diamond | 15 Tickets |
| Solve without a check (perfect) | +25 Tickets |
| First Facet (first solve) | 💎 Bronze · 10 Tickets |
| Flawless Cut (no checks) | ✨ Silver · 20 Tickets |
| Polished (3-day streak) | 🔥 Bronze · 15 Tickets |
| Master Jeweller (7-day streak) | 💍 Gold · 40 Tickets |
| Crown Jewel (30-day streak) | 👑 Legendary · 100 Tickets |
VERSION HISTORY
- Launch version in Daily Brains.
- Procedural diamonds with solver-proven unique solutions; weekday ramp from a 3-wide Monday to a 6-wide, four-clue Sunday.
- Sum and gap crowns, product and free pavilions, no-repeat diagonals, ruby and sapphire gems.
- Pencil marks, automatic rule-break highlighting, rows that light up when polished, a check that costs points, emoji diamond share card.