Strata
Read the rock: order the events that wrote a section from what cuts what and what rests on what.
4
levels3–12 min
a run, player-paced3
samplesNo timer
player-paced, always
Strata
Read the rock: order the events that wrote a section from what cuts what and what rests on what.
A section of rock — beds, faults, dykes, erosion surfaces — and a bench of history cards. Arrange the cards into the sequence that produced it, oldest first, and commit. The rock's own relations mark the sequence, and a broken one is named with the principle it breaks. In the last section the relations run out, and a probe card that dates a dyke is how to finish the reading.
Levels
4 levelsThe tag on each level says how it gets harder. Levels gate on ideas, not on each other — jump wherever it gets interesting.
What decides the outcome
The game never restates the science — it imports it. These are the model layers that do the deciding.
The relative-dating relations and the check against them (stratigraphy: checkOrder, the principles, and undeterminedPairs — what a section cannot order), the three sections widget 39 ships, and the K–Ar age equation with its branching correction (geochronology, on physics' decay law). The game states no geological principle of its own.
Why it teaches
The author's own delete-the-science argument: remove this game's substrate and there is nothing left to choose.
Every card's place is decided by a relation in the rock — superposition, cross-cutting, inclusions, original horizontality, lateral continuity, faunal succession — and the substrate checks the sequence against exactly those relations. Without them the cards have no ordering constraint at all; with them, a wrong guess comes back as the principle it broke. The finale adds the one thing relations cannot do: put two events that never touch in order, which needs a date.
Accessibility
The contract's declarations, stated before you commit to a run.
Keyboard
Playable start to finish from the keyboard.
Screen reader
Every move is narrated — the narration is the state, not a description of a picture.
Motion
Reduced-motion: consequences render statically.
Audio
Silent — no sound, and nothing on screen moves on its own.