Time runs downward; positive cells are to the right. Default and Explore reproduce bbchallenge.org (atlas/viz-spec.md): Default greys (black = 0 or never visited; for 3+ symbols, 1 is darker than the top symbol), head red after a move right and green after a move left; Explore draws nonzero cells on slate and colours the head by its state (A red, B orange, C blue, D green, E magenta, F cyan, G yellow). Blaze rows are power-of-two blocks of time (quality = averaged, speed = first time of the block); the width fits every cell visited. Records has one row per new leftmost/rightmost cell; State one row each time the machine enters the chosen state. The frame option keeps cell 0, the head, or a span edge in a fixed column.
Deep links: append #view=explore (default, explore, blaze, records, state), &state=B, &frame=head, &style=explore, &site=0, &large=1. Mouse wheel pans, Ctrl+wheel zooms, Alt+wheel zooms time only, drag pans. Keys: f fit, 1 square pixels, 0 reset, + / − zoom. The site view of Default is a static 400×500 squeeze exactly like the site's canvas; untick it to zoom into the full trace (row 0 is the start configuration there, and heads on fresh cells are always drawn).