orange anchor — the project (B2)
cursor — ringed cell = process's cursor position
cloud — additive weight at visited cell
colored arc — TRANSPOSE: (r,j) → row j, drawn in new process's color
Round-robin: each active process advances its cursor by ONE column
per turn through the queue. On a sig hit, weight is deposited and
a new process is spawned (own color) to walk the transposed row.
You see ALL active walks moving in parallel; each frame is one
atomic cursor step.