SpaceChem Bench: Crossover

research_tutorial_1point5 Easy Bonding & routing Single-reactor Sernimir II · SpaceChem Bench report →

Inputs: α Gold (Au), β Platinum (Pt). Output: ψ Platinum (Pt) ×10, ω Gold (Au) ×10.

In SpaceChem Bench, 16 LLMs each had one attempt at this SpaceChem puzzle, with 10 minutes to build a working solution and keep optimizing it, without seeing the community archive. 14 of 16 models solved it. No model found a new Pareto-frontier point beyond the frozen community archive.

14 / 16models solved it
137best LLM cycles (136 community)
0new frontier points

Records

ScoreCommunity bestBest LLMModel
Cycles136137GPT-6.1 Sol · +1%
Reactors11DeepSeek V4.1 Flash Ties record
Symbols1616DeepSeek V4.1 Flash Ties record

Community records from the community archive when we froze it on October 18, 2026. A point counts only after fresh-game replay and SChem’s precognition check.

Pareto frontier

Pareto explorer

Lower is better ↙
Loading interactive Pareto explorer…
Community archiveModel frontier pointNew frontier point
Select a point with the mouse or keyboard to inspect its scores and reactor blueprint.

Search over time

Loading puzzle trajectories…

Every model

ModelSolvedBest cyclesBest reactorsBest symbolsNew frontier points
01GPT-6.1 SolYes137116—
02GPT-6 AstraYes138116—
03Opus 5.5Yes138116—
04Muse Wonder 1.0Yes147116—
05DeepSeek V4.1 FlashYes155116—
06Fable 5.1Yes155116—
07Gemini 3.8 FlashYes155116—
08Gemini 4 ArgonYes155116—
09Kimi K3.1 ProYes155116—
10Grok 4.7Yes156116—
11Muse Spark 1.3Yes156116—
12Sonnet 5.5Yes157116—
13Haiku 5.5Yes175118—
14GPT-6 LunaYes192116—
15GLM-5.3No————
16MiMo-V2.6-ProNo————

Best scores can come from different solutions. New frontier points are not matched or beaten on all three scores by any community solution.

Best model solutions

These solutions are in SpaceChem Community Edition export format and released under the MIT License. All of this puzzle’s model solutions are on GitHub and Hugging Face.

GPT-6.1 Sol Fewest cycles

137 cycles · 1 reactor · 36 symbolsresearch_tutorial_1point5.137-1-36.txt on GitHub

Layout

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 ↓ → → ↑ ↓ → ← ↑ ↓ ← ↓ → → ↑ ↓ → ← ↑ ↓ ← S← S↑ GRAB GRAB GRAB GRAB IN α IN α IN β IN β OUT ψ OUT ψ DROP DROP DROP DROP OUT ω OUT ω

Running in the game

GPT-6.1 Sol solution running on research_tutorial_1point5 in SpaceChem
SpaceChem Community Edition export (research_tutorial_1point5.137-1-36.txt)
SOLUTION:Crossover,Player,0-0-0
COMPONENT:'empty-research-reactor',2,0,''
MEMBER:'instr-start',180,0,128,4,1,0,0
MEMBER:'instr-start',-90,0,32,1,6,0,0
MEMBER:'instr-arrow',90,0,64,1,1,0,0
MEMBER:'instr-arrow',0,0,64,1,2,0,0
MEMBER:'instr-arrow',0,0,64,1,3,0,0
MEMBER:'instr-arrow',-90,0,64,1,5,0,0
MEMBER:'instr-arrow',90,0,64,5,2,0,0
MEMBER:'instr-arrow',0,0,64,5,4,0,0
MEMBER:'instr-arrow',180,0,64,6,1,0,0
MEMBER:'instr-arrow',-90,0,64,6,3,0,0
MEMBER:'instr-arrow',90,0,64,6,4,0,0
MEMBER:'instr-arrow',180,0,64,6,5,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-grab',-1,1,128,1,5,0,0
MEMBER:'instr-input',-1,0,128,2,1,0,0
MEMBER:'instr-input',-1,1,128,2,5,0,0
MEMBER:'instr-input',-1,1,128,3,1,0,0
MEMBER:'instr-output',-1,0,128,6,2,0,0
MEMBER:'instr-grab',-1,2,128,6,3,0,0
MEMBER:'instr-grab',-1,2,128,6,4,0,0
MEMBER:'instr-output',-1,1,128,6,5,0,0
MEMBER:'instr-arrow',90,0,16,1,1,0,0
MEMBER:'instr-arrow',0,0,16,1,2,0,0
MEMBER:'instr-arrow',0,0,16,1,3,0,0
MEMBER:'instr-arrow',-90,0,16,1,5,0,0
MEMBER:'instr-arrow',90,0,16,5,2,0,0
MEMBER:'instr-arrow',0,0,16,5,4,0,0
MEMBER:'instr-arrow',180,0,16,6,1,0,0
MEMBER:'instr-arrow',-90,0,16,6,3,0,0
MEMBER:'instr-arrow',90,0,16,6,4,0,0
MEMBER:'instr-arrow',180,0,16,6,5,0,0
MEMBER:'instr-grab',-1,1,32,1,1,0,0
MEMBER:'instr-grab',-1,1,32,1,5,0,0
MEMBER:'instr-input',-1,0,32,2,1,0,0
MEMBER:'instr-output',-1,0,32,6,2,0,0
MEMBER:'instr-grab',-1,2,32,6,3,0,0
MEMBER:'instr-grab',-1,2,32,6,4,0,0
MEMBER:'instr-output',-1,1,32,6,5,0,0

DeepSeek V4.1 Flash Fewest reactorsFewest symbols

155 cycles · 1 reactor · 16 symbolsresearch_tutorial_1point5.155-1-16.txt on GitHub

Layout

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 ↓ → ← ↑ ↓ → ← ↑ S← S↓ GRAB IN α OUT ω DROP IN β GRAB OUT ψ DROP

Running in the game

DeepSeek V4.1 Flash solution running on research_tutorial_1point5 in SpaceChem
SpaceChem Community Edition export (research_tutorial_1point5.155-1-16.txt)
SOLUTION:Crossover,Player,0-0-0
COMPONENT:'empty-research-reactor',2,0,''
MEMBER:'instr-start',180,0,128,3,1,0,0
MEMBER:'instr-start',90,0,32,1,3,0,0
MEMBER:'instr-arrow',90,0,64,1,1,0,0
MEMBER:'instr-arrow',0,0,64,1,4,0,0
MEMBER:'instr-arrow',180,0,64,6,1,0,0
MEMBER:'instr-arrow',-90,0,64,6,4,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-input',-1,0,128,2,1,0,0
MEMBER:'instr-output',-1,1,128,6,3,0,0
MEMBER:'instr-grab',-1,2,128,6,4,0,0
MEMBER:'instr-arrow',90,0,16,1,2,0,0
MEMBER:'instr-arrow',0,0,16,1,5,0,0
MEMBER:'instr-arrow',180,0,16,6,2,0,0
MEMBER:'instr-arrow',-90,0,16,6,5,0,0
MEMBER:'instr-input',-1,1,32,1,4,0,0
MEMBER:'instr-grab',-1,1,32,1,5,0,0
MEMBER:'instr-output',-1,0,32,5,2,0,0
MEMBER:'instr-grab',-1,2,32,6,2,0,0