It is the view of a logic analyser and of the classic digital waveform graph. A line is given as samples on a fixed interval or as a list of edges, so a sparse capture of a long idle period costs what it has to say. The view pans and zooms, cursors read every line and every bus at two instants and the time between them, and where more transitions land on a pixel column than it can show, the column is drawn as a block, which is what a real analyser does.
Chip select falls, the clock runs for three bytes, and the data lines carry a register write: command 0x0B, address 0x2A, value 0xC7. The bus rows read the byte on each edge group. Drag a cursor onto a clock edge or press the arrow keys to step it, use the wheel to zoom about the pointer, hold Shift and drag to zoom into a box, and double-click to fit.
Eight inputs and outputs of a packaging machine over eight hours, recorded as edges: an infeed sensor that pulses per product, a jam input, the run output and the guard interlock. A line with a few hundred edges over eight hours is drawn from its edges, and the cursors read the state of every line at two instants.
Keyboard: the plot is a tab stop. The arrow keys move the active cursor, with Shift by ten steps; N makes the next cursor active; + and - zoom, 0 fits, Home and End move the cursor to the ends of the view. The cursor legend is text, so the readings are available to a screen reader.