yrlyrl/spatial-mmcot-zebra_jigsaw

Spatial MMCoT v1 · zebra_jigsaw

Zebra-CoT visual jigsaw, type-2 (single-image) rows only, on ImageNet images (mostly photographs; some are web graphics such as banners and flyer templates). Each row has one input image: the source image with its missing piece(s) greyed out, above a panel of four candidate piece sets labelled A-D. The options exist only in that image, so the answer is the letter. The target is the complete source image. Type-1 rows are excluded: three quarters of their target images are deliberately wrong assemblies, and their text leaks the answer. The input is upstream's 2400x1800 puzzle sheet downscaled to 512x384, so each candidate piece is about 4.7 times smaller per side than upstream; the targets keep their ImageNet size (mostly 500 px on the long edge). On some rows the upstream final thought only restates the task and never says which option it picked; the choice is then only in <answer>. The thoughts keep upstream's numbered labels ('THOUGHT 0:', 'THOUGHT 1:', ...) inside <think>. They count upstream's thoughts across the whole trace, not the row's slots, so one slot often holds two or more labelled thoughts, and a slot after a target image can open with the unlabelled end of the previous thought. No other source in this release has these labels; if you mix sources and do not want a model to learn them, remove them with re.sub(r'THOUGHT \d+:\s*', '', text).

Supervision kind (supervision_kind in meta): full_interleaved on every row: the upstream trace itself interleaves text and target images (drawn or rendered states on most sources; the source note above says which), and the read-back comes after the target image it reads. The text is upstream's and was not checked against the images.

Upstream: multimodal-reasoning-lab/Zebra-CoT. Licence: cc-by-nc-4.0. This is the licence Zebra-CoT declares. The images are ImageNet images: copyright stays with their original rights holders (mostly photographers, some of whom are credited in the image itself; for the web graphics, the companies or designers who made them), and ImageNet's terms of access (https://image-net.org/download.php: non-commercial research and educational use only, and passing the images on only to people who agree to those terms) apply as well. Changes from upstream: every image is decoded and re-encoded as JPEG, the input at 512x384 and the target at its ImageNet size (at most 1,024 px); the image placeholders in the question and the reasoning were removed and the sentence around each repaired, sometimes by inserting words such as 'the image'; the reasoning is split into one thought per target; the ThinkMorph system prompt is prepended to the question; rows were filtered and balanced as described below.

Known issues

Rows with a measured per-row problem are listed in reports/known_issues/, one TSV per issue (a # <description> line, then row_uid<TAB>split<TAB>detail lines), so they can be filtered out. They are still in this release: no row was removed for these issues.

issue	rows	train	validation	what	how it was found	file
readback_names_no_option	1,077	1,039	38	The final thought never says which option it picked; the choice is only in <answer>.	after removing enumerations ('options A, B, C and D', 'A-D'), the read-back names no option: no 'option/choice/set/piece/answer X', no 'is X.', no quoted '(X)'/'X', no 'the second option'; measured 2026-09-25; known_issues.py sha1 655e5307; export 4aaee1f rows 0d29a930/872a902f	reports/known_issues/readback_names_no_option.tsv
text_says_options_not_shown	64	60	4	The upstream text says the options are not shown or cites a trace, template or answer the model never sees ('options (not shown, but implied by the original trace)'), although every input image draws options A-D; training on it teaches the model to deny visible options.	the question or any thought matches 'not shown|not provided|original trace|in the trace|implied by|template indicates|options are not|inferred from the answer' (the review's pattern); measured 2026-09-25; known_issues.py sha1 655e5307; export 4aaee1f rows 0d29a930/872a902f	reports/known_issues/text_says_options_not_shown.tsv
target_shared_with_other_row	16	16	0	The target photograph is also the target of another shipped row: one ImageNet photograph cut into two different puzzles (the inputs differ).	sha1 of the target image bytes occurs on more than one shipped row; measured 2026-09-25; known_issues.py sha1 655e5307; export 4aaee1f rows 0d29a930/872a902f	reports/known_issues/target_shared_with_other_row.tsv
question_states_answer	1	1	0	The question itself names the answer letter ('implied by the reasoning trace referencing option B').	after removing enumerations ('option (A, B, C, or D)'), the question text contains 'option X' where X is <answer>; measured 2026-09-25; known_issues.py sha1 655e5307; export 4aaee1f rows 0d29a930/872a902f	reports/known_issues/question_states_answer.tsv

To leave the listed rows out (the snippet in the loader section downloads reports/known_issues/ with the data):

import glob, os
root = "<root>/zebra_jigsaw"
drop = {line.split("\t")[0] for f in glob.glob(os.path.join(root, "reports/known_issues/*.tsv"))
        for line in open(f) if line.strip() and not line.startswith(("#", "row_uid\t"))}
# keep a row when its row_uid (a column of train/, meta/ and preview/) is not in drop

Measured caveats

Measured on this release by the pre-publication review (2026-09-25): problems that cannot be listed row by row (a shortcut in the options, a label convention, an upstream labelling scheme) and what the review found around the lists above. Where a caveat counts listed rows ("listed as ..."), the count is the table's, read from reports/known_issues/summary.json. Its other numbers are the review's own measurements, which no file carries: they hold for exactly these rows and are not re-measured automatically. Items marked Training-signal defect are problems in what the rows teach, not only in how they are described; no row was removed for them.

• Training-signal defect. On 64 rows (60 train, 4 validation; listed as text_says_options_not_shown) the upstream text says the options are not shown, or that the letter comes from 'the original trace', 'the template' or 'the answer', although every input image draws the A-D panel (e.g. f16546ecab8e2866: 'the available options (not shown, but implied by the original trace), option D'). On 5 training rows the question itself says the options are "(not shown)" or "(not provided)", and on 1 row the question names the answer (e.g. c1f61e2fe9424078; listed as question_states_answer). These rows teach the model to deny options it can see and to cite a trace it does not have.
• On 1,077 rows (1,039 train, 38 validation; listed as readback_names_no_option), 9.8% of the 10,962 rows, the upstream final thought only restates the task and never says which option it picked; the choice is then only in <answer>. No final thought picks a different option from <answer>, and no plan names the answer letter.
• The target_image_kind column in meta reads grid_state on every row. That is a mislabel: the target is the complete original image (a reconstruction), not a board state, so leave these rows out if you filter on grid_state to get grid puzzles.
• All 74 rows dropped at S8 (S8.k_zero) lost their only target to the minimum-size check: its long edge was under 256 px (100-255 px). build/dropped.jsonl does not record this reason.

Size

split	rows	target image slots	distinct target images
train	10,643	10,643	10,635
validation	319	319	319

A slot is one target position in one row. Some training rows are different puzzles cut from the same image: their inputs differ but their target, the complete image, is the same (they share a geometry_uid, not a scene_id), so there are fewer distinct target images (by content hash) than slots.

task	train	validation
visual_jigsaw	10,643	319

Input images per row: 1. Target images per row (the images the model is trained to generate): 1. Image corpus (source_scene_corpus): imagenet 10,962.

Row format

One row is: input image(s) and a question, then K rounds of thought → target image (the target is the source's own ground-truth image, which the model is trained to generate), then a final thought (normally a read-back of the last target; where a source's final thought is something else, or often leaves out the answer, the source note or Known issues says so) and the answer; here K is 1. In the train config:

image_list        list<binary>  inputs first, then the K target images in order
num_input_images  int64         how many of image_list are inputs
instruction_list  list<string>  one element: system prompt + question; the options A-D are drawn in the input image, there is no option text
output_text_list  list<string>  K+1 elements:
  [0]   <think>plan 1</think><image_start>
  [j]   <image_end><think>plan j+1</think><image_start>
  [K]   <image_end><think>read-back</think><answer>answer</answer>
row_uid           string        join key to `meta` and `preview`

Every image is a JPEG, and no input image is larger than 512 px on its long edge (measured on this release, 2026-09-25); the size each target was stored at is target_px in meta.

<answer> holds exactly meta.answer_value (also the answer column of preview) on every row: score model output against that string.

The system prompt is ThinkMorph's VLM_THINK_SYSTEM_PROMPT from its inferencer.py, verbatim (GEN_THINK_SYSTEM_PROMPT there has the same text), including its leading and trailing newline. The markers are plain strings, not tokenizer special tokens; the prompt writes </image_end> and the data writes <image_end>, exactly as the ThinkMorph-7B checkpoint was trained.

preview shows the same rows with one column per slot: input_image_i for the inputs; for each of the K = num_steps rounds, the plan thought_j and its target target_image_j; and the read-back in thought_1 on every row.

meta holds the per-row sidecar: task, scene_id and geometry_uid (the scene and geometry keys; the split key is named in the split paragraph below), trajectory_id (a camera-path or sample label, empty where the source has none), num_steps, num_input_images, answer_type, answer_value, majority_class_rate, target_image_kind, target_px, est_tokens, licence, split (train / validation, the Hub split names), supervision_kind (full_interleaved / visual_aux / visual_only) and filter_flags. majority_class_rate is the share of the task's most frequent answer_value among its training rows: it measures answer skew and is not a guessing baseline (where a task mixes question types or each row has its own options it can be far below chance); compare scores with the text-only baselines below.

Per-row license in meta: cc-by-nc-4.0 10,962.

Flags on released rows (filter_flags in meta and preview, comma-separated):

flag	rows	meaning
S5.replay_unsupported	10,962	no solver re-derives this task's answer from the trace, so S5 did not replay it
S14.sampled_qa	200	chosen for the S14 human spot-check (reports/s14_sample.tsv)

Training with a BAGEL-family loader

Every row here has one input image (num_input_images is 1), so the stock ThinkMorph UnifiedEditIterableDataset (https://github.com/ThinkMorph/ThinkMorph: image_list[0] as input, image_list[j+1] after output_text_list[j]) and the IPT release's version (which reads num_input_images) both read it as intended. Mixed with a source whose rows have more than one input image, only a loader that reads num_input_images is correct.

The stock BAGEL edit loader (ByteDance-Seed/Bagel) cannot train these rows: it never reads output_text_list and expects each instruction_list element to be a list of paraphrases.

parquet_info.json keys each training chunk as <source>/<split>/<file>, here zebra_jigsaw/train/chunk_00000.parquet, with row-group counts read from the parquet footers. The loader matches a chunk only when its key equals the path it builds, os.path.join(data_dir, file), and skips a chunk with no key without a warning: a source that is alone in its group then fails with IndexError: list index out of range, and in a mixed group it adds no rows. Download into a directory named after the source, not after the repository:

from huggingface_hub import snapshot_download
snapshot_download("yrlyrl/spatial-mmcot-zebra_jigsaw", repo_type="dataset", local_dir="<root>/zebra_jigsaw",
                  allow_patterns=["train/*", "validation/*", "parquet_info.json", "reports/known_issues/*"])

Then either run from <root> with data_dir: zebra_jigsaw/train and parquet_info_path: zebra_jigsaw/parquet_info.json, or rebuild the index with absolute keys and use an absolute data_dir:

import json, os
root = "/abs/path/to/root"                      # the directory that holds zebra_jigsaw/
info = json.load(open(os.path.join(root, "zebra_jigsaw", "parquet_info.json")))
info = {os.path.join(root, k): v for k, v in info.items()}
json.dump(info, open(os.path.join(root, "zebra_jigsaw", "parquet_info_abs.json"), "w"))
# data_dir = os.path.join(root, "zebra_jigsaw", "train")   (spelled exactly so, no trailing slash)
# parquet_info_path = os.path.join(root, "zebra_jigsaw", "parquet_info_abs.json")

The Hugging Face cache (.../snapshots/<hash>/train/) or a folder named spatial-mmcot-zebra_jigsaw matches no key.

num_used_data counts chunk files, not rows: the loader repeats this source's file list up to that number, lists every (file, row group) pair, and deals whole row groups out, floor(R / world_size) to each rank and floor(that / num_workers) to each DataLoader worker. The remainder is never read. This source has 1 training chunk file holding 84 row groups of up to 128 rows, so keep num_used_data large, e.g. the 128 of ThinkMorph's interleaved_reasoning.yaml (upstream's example.yaml asks for more than GPUs x workers); every row group is then read. Set to 1 and alone in its group on 8 GPUs with 4 workers, it reads only 64 of the 84 row groups. In a run that mixes sources, give each source the same multiple of its own training chunk-file count, e.g. 128 per file (128 here): the file list is repeated up to num_used_data entries, so a flat 128 for every source would read a two-file source's rows half as often as a one-file source's.

How the rows were chosen

stage	rows
upstream rows read	21,899
refused before conversion (S0raw; each reason is in the table below)	10,862
dropped at S5 (the text contains a phrase from S5's self-contradiction list, e.g. 'does not make sense', 'discrepancy', 'there must be a mistake'; a keyword match, not a comparison with the images, so it also removes some sound rows)	1
dropped at S8 (a target was removed as a copy of an input, as transparent or as too small, and the row had no target left or was a multi-step chain that cannot lose a state)	74
after conversion and per-row filters	10,962
removed by S10 (none)	0
removed by answer-prior balancing (S13)	0
released	10,962

The rows refused before conversion are exactly the upstream rows whose trace carries four reasoning images: the type-1 puzzles, where three of the four candidate assemblies are deliberately wrong and the trace names the answer before any image is drawn. That rule, not the ids in build/dropped.jsonl, reproduces the refused set.

Every removed row has one line, with its reason, in reports/:

file	step	reason (the line's flag, or the field shown)	rows
build/dropped.jsonl	S0raw	S7.multi_option_targets	10,862
build/dropped.jsonl	S5	S5.self_contradiction	1
build/dropped.jsonl	S8	S8.k_zero	74

S0raw lines in build/dropped.jsonl were refused before a release row existed, so their row_uid field holds the converter's key for the upstream record, not a 16-hex row_uid; lines from later steps carry the row_uid the row had. No removed row appears in meta or preview. For this source the key is built from upstream fields that repeat across rows (for most sources a hash of the question text), so it is not unique: the 10,862 S7.multi_option_targets lines carry 9,862 distinct keys. Those rows are counted with their reason but cannot be traced to individual upstream rows.

S8.k_zero and S8.chain_broken name what happened to the row, not which check removed the image; the lines in this build do not record whether it was the size, transparency or copy check.

Per-step counters of the conversion

21,899 upstream rows were read; S0raw refused 10,862 before a row existed and passed 11,037 to the first step. S0 runs once more, last, on the final bytes. The reason for every refused, dropped or quarantined row is in the files above.

step	in	out	dropped	quarantined	rejected	repaired
S0raw (refused before conversion)	21,899	11,037	0	0	10,862	0
S4	11,037	11,037	0	0	0	0
S4c	11,037	11,037	0	0	0	0
S5	11,037	11,036	1	0	0	0
S8	11,036	10,962	74	0	0	0
S9	10,962	10,962	0	0	0	0
S0 (final structural check, after S9)	10,962	10,962	0	0	0	0

The train/validation split keeps rows sharing a geometry_uid in meta on one side, and the assignment is frozen (splits/ in the summary repository). geometry_uid is a hash of the upstream target, the complete source image, so puzzles cut from one image stay on one side; scene_id here is a per-puzzle hash of the input. S12 saw 10,962 rows under 10,954 keys. No validation input image has the content of a training input image, and none is a pixel-level near-copy of one. S12 does not record per source whether that test ran, but it skips it only for a source whose spec sets split_leak_pixels: false, and no spec does; over all sources it compared 21,661 candidate pairs (perceptual hash within 6 bits) pixel by pixel and found no near-copy (checked 2026-09-25).

Answer-prior balancing (S13)

Each (task, split) group is checked separately. An answer is the answer value compared as lower-cased text without a trailing full stop, with 'farther' read as 'further' and 'nearer' as 'closer' (for multiple choice, the option text, not the letter; where the candidates are drawn in the image, as in zebra_jigsaw and zebra_tetris, the answer is the letter itself). An answer is real when it holds at least 5 rows and 2% of the group; k is the number of real answers. Answer step: the target is max(30%, 1/k) when k >= 2, and max(30%, 1/d) over the d distinct answers when k = 1; a validation group uses the larger of its own target and its task's train target. A group is cut only when k >= 1 and its most common answer holds more than the target plus 5 percentage points; every answer is then capped at one common count, chosen so that none exceeds the target, and smaller answers keep all their rows. At the answer step, a group at or below that trigger, or with no real answer (k = 0), is left as it is, so its most common answer can hold up to the target plus 5 percentage points. A task whose train group has exactly two real answers is instead cut, in every split, so that its two largest answers have equal counts, with no trigger. Rank and label steps: then, in a group where every option value of every row is a number, the rank of the correct option among the sorted values, and after it, in a group where every trained answer is an option label, the label, are each capped by the same cut-and-trigger rule on their own counts (own target, validation included): capped, never evened out, so two labels are cut only when one exceeds 55%, and then only down to 50%. These steps can also cut groups the answer step left whole, including k = 0 groups, and can raise an answer's final share above its target; the run fails if a real answer ends above the target plus 5 percentage points. A train group of at least 20 rows in which one answer holds 90% or more fails the run. PET (exact_cells_pet) instead cuts each (question type x turn direction) cell to equal counts of its two answers; a PET cell that shows only one answer is removed.

task	split	pass	rule	rows in → out	real answers k	target	largest share, before → after	cut
visual_jigsaw	train	answer	cap30[canon]	10,643 → 10,643	4	30.0%	25.3% → 25.3%	no
visual_jigsaw	train	letter	cap30[letter]	10,643 → 10,643	4	30.0%	25.3% → 25.3%	no
visual_jigsaw	validation	answer	cap30[canon]	319 → 319	4	30.0%	29.5% → 29.5%	no
visual_jigsaw	validation	letter	cap30[letter]	319 → 319	4	30.0%	29.5% → 29.5%	no

S13 removed no row from this source.

Text-only baselines

Accuracy of guessers that never see an image. For each task the released training rows are split into two fixed halves by a hash of row_uid; each guesser is fitted on one half and scored once on the other (one held-out half, not cross-validation; eval rows below). The reference is chance (the mean of 1 / number of options) where every row is multiple choice, and otherwise the eval-half accuracy of always giving the answer most common in the fit half (when a task's top answers are nearly tied, this need not be the task's most common answer; the line after the table gives that answer's validation score). Accuracies are recounted from the stored rates and eval rows, so they are exact. A task is flagged when a text-only guesser beats its reference by more than 0.15 (for a free-form task, a guesser other than the most common answer). A flagged task can be partly answered from the text alone; an unflagged task passed only these probes, which do not prove the text carries no answer. Report scores on every task next to this baseline.

Guessers: keywords: the most common answer per set of spatial words in the question; last_mentioned: the option named last in the question body; letter_prior: the most common answer letter; majority: the answer most common in the fit half; option_prior: the option text that won most often when shown; template: the most common answer per question wording (numbers masked, object names kept).

task	best text-only guesser	accuracy	reference	margin	eval rows	flagged
visual_jigsaw	majority	0.252	0.250 (chance)	+0.002	5,382	no

Spot-check (S14)

Pending. The S14 rows are chosen and flagged S14.sampled_qa in meta and preview; the human pass over them has not been signed off yet.

Citation

Zebra-CoT is by Ang Li, Charles Wang, Deqing Fu, Kaiyu Yue, Zikui Cai, Wang Bill Zhu, Ollie Liu, Peng Guo, Willie Neiswanger, Furong Huang, Tom Goldstein and Micah Goldblum, released under CC BY-NC 4.0; this repository is a converted subset of it (the changes are listed under the licence line above). Its card asks users to cite:

@inproceedings{li2026zebracot,
  title={Zebra-CoT: A Dataset for Interleaved Vision-Language Reasoning},
  author={Ang Li and Charles Wang and Deqing Fu and Kaiyu Yue and Zikui Cai and Wang Bill Zhu and Ollie Liu and Peng Guo and Willie Neiswanger and Furong Huang and Tom Goldstein and Micah Goldblum},
  booktitle={The Fourteenth International Conference on Learning Representations},
  year={2026},
  url={https://openreview.net/forum?id=c6XIVI3TiQ}
}

The images are ImageNet's; please also cite J. Deng, W. Dong, R. Socher, L.-J. Li, K. Li and L. Fei-Fei, "ImageNet: A Large-Scale Hierarchical Image Database", CVPR 2009 (https://image-net.org/).

Provenance

The release files were written by our conversion code (the code repository is not public yet), scripts/convert/export.py at commit 4aaee1f4e946, from build zebra_jigsaw_r2. The build was made by scripts/convert/run_source.py from the same repository at commit 949af62f8ab7. S10, S12 and S13 ran before the export; reports/export_manifest.json pins every input the export read by SHA-1 (build_manifest_sha1, s10_keep_sha1, s12_assignments_sha1, s13_balanced_keep_sha1).

Every row removed between upstream and this release has one line, with its reason, in reports/: build/dropped.jsonl (rows refused before conversion or dropped by a conversion step); build/quarantine.jsonl (rows set aside by S4c because an automatic check could not match the read-back's conclusion to the label); s10_dropped.jsonl (duplicates removed by S10); s10_label_conflicts.jsonl (rows S10 withheld because another row asks the identical question, options in the same order, of the same images with a different answer); s13_dropped.jsonl (rows removed by answer-prior balancing). known_issues/ lists rows with a measured problem (see Known issues); reports/ also holds the build manifest (absolute paths cut to basenames) and counters, the S14 sample list (s14_sample.tsv: row_uid, task, split) and export_manifest.json. Part of yrlyrl/spatial-mmcot.