STEALTHMARK · HEAD TO HEAD
All comparisons ↗Fledge Alpha vs GPT-6.1 Terra Low
GPT-6.1 Terra Low leads Fledge Alpha by 5.5 points on StealthMark, 41.3 to 35.8. Fledge Alpha and GPT-6.1 Terra Low each lead on 3 of the 7 benchmarks with results for both, with 1 tied. GPT-6.1 Terra Low scores higher on Newton's Mirror, with its largest category advantage in state at 600 ms.
See the difference ↘Overall StealthMark
General Intelligence
Visual Intelligence
BENCHMARK BY BENCHMARK
Where each model leads
- Fledge Alpha
- GPT-6.1 Terra Low
- Other models
- Median
Games
SVG
DATASHEET
Specs and pricing
- Fledge Alpha
- GPT-6.1 Terra Low
- Other models
- Median
Foresight
Play Foresight yourselfAnticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.
GPT-6.1 Terra Low 36.1/100Rank 26/51

Points per level
Latch
Play Latch yourselfCooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.
Fledge AlphaNo run
GPT-6.1 Terra Low 62.4/100Rank 23/52

Points per level
Newton's Mirror
Same task instructionsPhysics, perspective and recursive reflections, tested together. Explore the test ↗
Fledge Alpha 16.4/100 Rank 43/55

GPT-6.1 Terra Low 27.6/100 Rank 30/55

The judgment
Fledge Alpha
The candidate communicates a round metallic sphere, three paint colors and a separate airborne black blob. Its hovering support relationship, displaced framing and unresolved paint interaction limit physical credit. Sparse planar light ghosts and a soft sphere highlight provide little evidence for the required wall/floor repetitions and curved nested mirror imagery.
GPT-6.1 Terra Low
Deformed colored paint and a separate airborne black body establish readable interaction history. Cyan has travelled too far, framing differs substantially, and the mirror system supplies only elementary bands and oval copies. Missing recursive geometry, nested spherical imagery and emitter mapping remain the dominant weaknesses.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra Low |
|---|---|---|
| State at 600 ms | 9.0/25 | 22.0/25 |
| Camera and placement | 5.0/15 | 4.0/15 |
| Reflections | 7.5/120 | 10.0/120 |
| Materials and scale | 3.5/10 | 6.0/10 |
| Floor-damage reward | 0.0/10 | 0.0/10 |
Benchmark task
A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.
Selfie
Different task instructionsVisual construction and creative interpretation.
Fledge Alpha 61.1/100 Rank 31/55

GPT-6.1 Terra Low 45.5/100 Rank 46/55

The judgment
Fledge Alpha
A coherent, appealing mascot with expressive eyes, a cheerful beak and a readable swept-back silhouette. Its larger forward foot and trailing feathers suggest a running stride, but the upright body, stiff legs and minimally articulated feet limit convincing motion. Clean flat shapes suit the brief, while uneven feather junctions and incomplete cream accents reduce polish.
GPT-6.1 Terra Low
Six attached outward-facing heads, delicate scales and soft ivory shading establish an orderly decorative motif. Separate paddle-shaped bodies replace the required interlocking loops and leave no enclosed central hexagon. Surface detail provides interest, but repeated simple forms, schematic faces and limited anatomical modeling constrain the result.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra Low |
|---|---|---|
| Task & likeness | 7.5/10 | 4.0/10 |
| Anatomy & construction | 6.5/10 | 3.5/10 |
| Space & placement | 7.0/10 | 4.5/10 |
| Light & reflections | 5.5/10 | 5.5/10 |
| Purposeful detail | 6.5/10 | 5.5/10 |
| Artistry & character | 4.0/10 | 5.0/10 |
| Materials & effects | 6.0/10 | 5.5/10 |
| Visual integrity | 6.5/10 | 4.0/10 |
Benchmark task
Fledge Alpha
An eager young seabird running toward the viewer tests expressive anatomy, balance and a convincing forward-moving pose.
GPT-6.1 Terra Low
A pale serpent woven into an interlocking knot tests connected anatomy, repeated structure and readable overlaps. Organic surface detail must work with the overall geometry.
Mona Lisa
Different task instructionsPrecise visual recall and portrait reconstruction.
Fledge Alpha 28.3/100 Rank 37/55

GPT-6.1 Terra Low 51.9/100 Rank 12/55

The judgment
Fledge Alpha
A recognizable but basic Mona Lisa reinterpretation with a coherent silhouette and subdued palette. Curtain-like hair obscures much of the face, while elongated facial construction and oversized, minimally articulated hands substantially weaken replication. Soft shading supplies modest volume, but anatomy, landscape depth and purposeful detail remain underdeveloped.
GPT-6.1 Terra Low
A recognizable, coherent portrait with purposeful facial detail, warm local volume and layered scenery. The frontal pose, enlarged face, merged hands and shallow clothing construction substantially limit replication and drawing skill. The visible successes support retaining the current assessment.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra Low |
|---|---|---|
| Task & likeness | 3.0/10 | 5.0/10 |
| Anatomy & construction | 3.0/10 | 4.5/10 |
| Space & placement | 2.5/10 | 5.0/10 |
| Light & reflections | 2.5/10 | 6.0/10 |
| Purposeful detail | 3.0/10 | 5.0/10 |
| Artistry & character | 3.0/10 | 5.5/10 |
| Materials & effects | 2.5/10 | 5.0/10 |
| Visual integrity | 2.5/10 | 6.0/10 |
Benchmark task
An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.
Beach
Different task instructionsCreativity, perspective and visual beauty.
Fledge Alpha 43.4/100 Rank 47/55

GPT-6.1 Terra Low 61.6/100 Rank 27/55

The judgment
Fledge Alpha
A cheerful, recognizable sunset beach with a cohesive warm palette and clear accessories. Simple construction, uncertain palm support, an ambiguous upper boundary and schematic reflections limit depth and finish. The scene communicates its subject successfully but lacks the developed forms, lighting and detail of exceptional illustration.
GPT-6.1 Terra Low
A coherent sunset scene demonstrates the beach, animals, birds and reflections. Flowing silhouettes, warm color transitions and intact attachments are its strongest properties. Simplified anatomy, the turtle's elevated viewing angle and symbolic surface effects constrain drawing complexity and physical depth.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra Low |
|---|---|---|
| Task & likeness | 7.5/10 | 8.0/10 |
| Anatomy & construction | 4.0/10 | 5.5/10 |
| Space & placement | 5.5/10 | 5.5/10 |
| Light & reflections | 5.0/10 | 6.5/10 |
| Purposeful detail | 3.0/10 | 6.0/10 |
| Artistry & character | 3.0/10 | 5.0/10 |
| Materials & effects | 2.5/10 | 5.5/10 |
| Visual integrity | 4.0/10 | 7.5/10 |
Benchmark task
A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.
Ground Truth
Same task instructionsPhysical reasoning, light and visual reconstruction.
Fledge Alpha 36.8/100 Rank 33/55

GPT-6.1 Terra Low 27.2/100 Rank 44/55

The judgment
Fledge Alpha
This benchmark has not been assessed yet.
GPT-6.1 Terra Low
This benchmark has not been assessed yet.
Benchmark task
A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.
Raccoon
Same task instructionsScene composition and interacting subjects.
Fledge Alpha 63.4/100 Rank 20/55

GPT-6.1 Terra Low 54.0/100 Rank 31/55

The judgment
Fledge Alpha
An appealing sunset illustration with recognizable characters and a clear riding action. Color, expression and silhouette are stronger than anatomical construction: overlapping paws obscure support, the dog's steering limb is simplified, and the vehicle controls lack definition. The wake conveys movement, while lighting and water reflections remain decorative.
GPT-6.1 Terra Low
Recognizable animals, a coherent craft and sweeping wake make an appealing cartoon. Basic limb construction, weakly demonstrated raccoon seating and limited shared perspective constrain the scene. Small identifying details work well, while lighting and materials remain broadly graphic.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra Low |
|---|---|---|
| Task & likeness | 8.5/10 | 6.5/10 |
| Anatomy & construction | 5.5/10 | 5.0/10 |
| Space & placement | 7.5/10 | 5.5/10 |
| Light & reflections | 6.5/10 | 4.5/10 |
| Purposeful detail | 7.0/10 | 6.0/10 |
| Artistry & character | 5.5/10 | 5.0/10 |
| Materials & effects | 7.0/10 | 5.0/10 |
| Visual integrity | 4.5/10 | 6.0/10 |
Benchmark task
A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.
Pelican
Different task instructionsSubject construction and spatial relationships.
Fledge Alpha 60.5/100 Rank 35/55

GPT-6.1 Terra Low 60.5/100 Rank 35/55

The judgment
Fledge Alpha
A clear, cheerful illustration with a recognizable pelican, coherent bicycle silhouette and tidy composition. Simplified leg articulation, steering contact, mechanical detail and lighting keep it at a competent illustrative level.
GPT-6.1 Terra Low
A coherent coastal illustration with a distinctive pelican, controlled contours and clearly organised bicycle wheels. Visible saddle support and shaped neck and wing contours earn credit beyond basic geometric construction. Rubbery legs, unresolved pedal contacts and absent steering contact limit the riding action. Lighting and materials remain restrained and spatially shallow.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra Low |
|---|---|---|
| Task & likeness | 8.0/10 | 7.0/10 |
| Anatomy & construction | 6.0/10 | 5.5/10 |
| Space & placement | 6.5/10 | 6.0/10 |
| Light & reflections | 4.5/10 | 5.5/10 |
| Purposeful detail | 5.5/10 | 6.5/10 |
| Artistry & character | 5.0/10 | 6.0/10 |
| Materials & effects | 5.5/10 | 6.0/10 |
| Visual integrity | 6.5/10 | 6.0/10 |
Benchmark task
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.