Wire user input to state through the Elm Architecture's three pure functions: init, update, and view. Model the counter app as a struct, define Msg as an exhaustive enum, and run crossterm's poll/read loop with raw mode. Map every KeyEvent through a total dispatch function so update never sees noise, and exit cleanly on Esc, Ctrl-C, or q.

Compose widgets that do real work — Sparklines from eight Unicode block glyphs, BrailleGraphs at 4x resolution, a CpuGrid that wraps one cell per core, a ProcessTable that scrolls, and a MemoryBar that fills. Each widget is one paint(rect) call; together they form a live system-monitor TUI.

Move from imperative paint calls to declarative scenes. Write .prs files that describe layout, then watch a 200-line recursive-descent compiler reconcile them against your widgets. Lock the look with probar snapshot tests — stringified CellBuffers, inline or file-backed goldens, byte-identical between runs, all running in CI without a TTY.

Bring everything together: a deterministic Snapshot fixture feeds a single pure view that composes CpuGrid, Sparkline, MemoryBar, and ProcessTable into one ptop-mini dashboard, then swap the fixture for a /proc reader to run the same view live.