Every example page is a small instrument: hover a move, a type, or a word with a dotted underline. Arcs under a play are justifiers.
Opponent (ochre) starts; Proponent (teal) answers. A play is a justified sequence: each non-initial move points at the earlier move that enabled it.
A question opens a thread; an answer closes the question it points at. Well-bracketing is reported, not enforced.
Proponent is innocent: the next move depends only on the P-view of the current play. In a trace, washed (teal-tinted) tokens are in the P-view at the current step. Step through a play and watch the wash change.
The identity on A → A copies each Opponent move to the other component. Hover ₊ versus ₋ on the copier page: ₊ is the result, ₋ is the argument. Copycat is the universal information-passing relay.
Ω means the strategy has no move. … (bound) means the page stopped unfolding, not that the strategy died. Trees start with deeper Opponent branches folded — click the reply count to open them.
The same catalogue is on the command line: stack run game-semantics -- play copier. See docs/cli.md.