Era Staircase
Yesterday's monument supports tomorrow's city.
Hearth 16 → Market 32 → Observatory 64 · Built monuments ■ never move.
How to play
Raise the Hearth with an exact 16 at the bottom-right stair, then Market 32 directly above it, then Observatory 64 above that. A matching tile alone is not enough: press Raise monument. It becomes a permanent barrier and support for the next era.
Arrow controls slide every tile, merging equal neighbors once per shift. Monuments divide rows and columns into separate lanes, and tiles never pass through them. No random tile appears after a shift.
Select an empty cell to plant a seed. Each era supplies eight seeds: values 2, then 4, then 8. Raising a monument replaces unused old seeds with eight of the next era; existing ordinary tiles remain. Choosing where and when to plant matters.
40 successful shifts total; seeds and building do not spend shifts. A no-op or blocked plant costs nothing. A ready monument can still be raised after the final shift. If shifts run out without a ready monument, or no shift/seed placement remains, the civilization stalls.
Undo reverses planting, shifting or building, including seed refill and barriers, even after ending. Retry repeats the same open planning challenge. Tap cells and buttons or use arrow keys and Tab/Enter. Untimed.