
Daily Brains · six moments from history, stack them oldest to newest.
Time Stack is the history puzzle in Daily Brains (/daily). Each day deals six events — inventions, discoveries, eruptions, voyages, buildings and firsts from every corner of the world — in a jumbled vertical stack. Put them in order from oldest (top) to newest (bottom) in up to three tries. Everyone in the world gets the same six cards in the same starting order, and at the end the true years thud down onto the cards like rubber stamps.
453 events from Lascaux's cave paintings (c. 15,000 BCE) to a lander near the Moon's south pole (2023), each with an emoji, a short title and a one-line fun fact that is revealed at the end. Only well-established dates are used; events whose date is approximate are shown with “c.” and are only dealt next to events far enough away that their order can never be argued. No living people and no modern politics.
Six cards a day, always at least four years apart, never more than two from one era (before 1000, 1000–1599, 1600–1799, 1800s, 1900–1959, 1960 on), always at least four eras, and always at least one card from before 1600 and one from after 1900. The deck is dealt least-recently-used first on a fixed schedule from puzzle #1, so a card rests for at least 75 days before it can come round again. The starting shuffle is seeded by the puzzle number and never has more than one card already in place.
The cards hang off a glowing timeline spine that runs from sepia at the top (the deep past) to blue at the bottom (today), with a pulse of light flowing down it. Each slot has a node on the spine that turns green or amber as you get feedback.
Drag a card up or down to slide it into a new slot, or tap one card and then another to swap them. On a keyboard, 1–6 picks the card in that slot, ↑ and ↓ move it, Esc drops it and Enter locks in your order.
Lock it in and every card is graded where it sits: green (✓) means it is in exactly the right slot and it locks there for the rest of the day; amber (±1) means it is one slot away from where it belongs; plain means further off. Locked cards never move — dragging slides the other cards around them.
Solve it on the first try for 300 points (a perfect day), the second for 200, the third for 100. Run out of tries and each card that was in its right slot on your last try still earns 10. Solving keeps your streak alive.
When the day ends the stack settles into the true order and each year is stamped onto its card in turn; tap any card to read its fun fact, or open the results for the full recap. The share text is spoiler-free: one row of 🟩🟨⬜ squares per try, the score and a link.
| Result | Points |
|---|---|
| Solved on try 1 (perfect) | 300 |
| Solved on try 2 | 200 |
| Solved on try 3 | 100 |
| Out of tries | 10 per card in its right slot |
| Event | Reward |
|---|---|
| Solve the stack | 15 Tickets |
| Solve it first try (perfect) | +25 Tickets |
| Chronicler (first solve) | 📜 Bronze · 10 Tickets |
| Keeper of Ages (perfect stack) | ⏳ Silver · 20 Tickets |
| Three Eras (3-day streak) | 🔥 Bronze · 15 Tickets |
| Almanac (7-day streak) | 📅 Gold · 40 Tickets |
| Living History (30-day streak) | 🏛️ Legendary · 100 Tickets |
| Era | Events |
|---|---|
| Before 1000 CE | 88 |
| 1000–1599 | 77 |
| 1600–1799 | 78 |
| 1800–1899 | 79 |
| 1900–1959 | 59 |
| 1960 onward | 72 |