role tints
(untick to see the raw cells, white = 1 and black = 0, exactly as the diagram renderer drew them; browser zoom keeps everything sharp)
Tints show what each stretch of cells is (parsed from that row); under them is the raw tape: light = 1, dark = 0; green = head.
(10)(10)… run at the left end
marker 11001
tail (10)…(10)1
pair: its (10)-run
pair: its (01)-run
digit block: 0001 = 1, 0010 = 0
Magnified: cells -17..12 of rows 8,129 and 8,945 (red box below). One count-down step touches pair 2:
step 8,129
counter 4
(10)-run, pair 2
(01)-run, q = 4
0010 = 0
pair 3 →
1
0
1
0
1
0
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
step 8,945
counter 3
(10)-run, pair 2
(01)-run, q = 3
0001 = 1
pair 3 →
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
0
0
1
1
0
1
0
its (10)|(01) border moved
2 cells right (q 4 → 3);
its digit block flipped
0010 → 0001 in place.
Pairs 1 and 3 were touched
too (outside this box).
Every cell, one row per count-down step; time runs down.
old (10)|(01) border, carried across a re-pair band
old digit block (its middle), the same way
step
counter
pair 1 →
pair 2 →
3,520
2
re-paired
4,012
1
−1
4,468
0
−1
5,100
1
End: + tail
5,684
0
−1
pair 1 →
pair 2 →
pair 3
RE-PAIR ↓
6,965
6
re-paired
7,577
5
−1
8,129
4
−1
8,945
3
−1
9,625
2
−1
10,493
1
−1
11,301
0
−1
12,389
3
End: pair 3 → tail
13,325
2
−1
14,453
1
−1, pair 2 → tail
15,517
0
−1
pair 1 →
pair 2 →
RE-PAIR ↓
17,738
2
re-paired
18,838
1
−1
19,630
0
−1
20,870
1
End: + tail
21,790
0
−1
← cells -152..47, 1 cell = 3 px. The (10)-run at the left end runs past the left edge on later rows (it grows 8 cells per row).