Does the drawing change its habits?
Compare the beginning and end of an accepted-stroke record, then ask how unusual their differences are under shuffled order.
Source image
Candidate marks
Click a cellImage measurements
How to interpret this view
This is a spatial analysis of a single flattened image, not a time series. Dark and light modes use sRGB luminance on a white background, selecting pixels at or below or at or above the cutoff. Local contrast selects pixels that differ from their 31 × 31 neighborhood mean by at least the cutoff, including neighboring pixels outside the region. Coverage and centroid describe pixel values, not individual strokes; they depend on the threshold, image boundaries, lighting, background, and resizing. A photograph, scan, or image with a dark ground may need different settings. Candidates are 8-connected components of dark pixels within the selected region. Touching marks merge; a textured mark may split into many pieces. Orientation is the principal axis of each component’s pixel coordinates; near-round components have unstable orientation. Export includes settings and candidate geometry, not the source image.
Early phase
Late phase
Phase profiles
Direction and mark IDsObserved difference vs. shuffled order
Select Run shuffle testSelected region
Interpretation & provenance
Are the early and late groups more different than two equally sized groups drawn without replacement from this same record? Every shuffle reassigns strokes to order; it preserves the marks but destroys their original order. A small p-value describes evidence against that exchangeability baseline, not proof of an artistic intention.
Length difference is the absolute difference in mean polyline length. Centroid distance uses start positions normalized by canvas width and height. Mark difference is total variation distance between mark-ID proportions (0 = identical; 1 = disjoint). Differences are unsigned. Playback reveals each phase in accepted-stroke order; phase statistics and tests always use complete phases. The three comparisons are exploratory and unadjusted for multiple testing. Phase profiles summarize undirected segment orientations (0° horizontal, 90° vertical); concentration near zero means no single dominant axis.
The bundled examples are generated stroke sequences from the drawing-machine project. Strokes are drawn as centerlines, not a reconstruction of media, pressure, or erasure. Early and late groups exclude the middle and never overlap. Selecting a cell filters on the stroke's first point, not every point it crosses. No elapsed time is available.