Game setup
Choose a scenario, objective, difficulty, and learning constraints.
Classification
Seed: 42
Score
0
Accuracy, gain, simplicity
Train score
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Not tested
Test score
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Unseen records
Tree size
1
1 leaves
Best streak
0
Strong split streak
Time
03:00
Free build
Interactive tree canvas
Select a node, choose a feature, preview a split, then grow branches.
Active node: Root
Drag to pan · Wheel to zoom · Click nodes to edit
Dataset and prediction paths
Inspect records, filter samples, and select one for animated routing.
Select a record to inspect its route through the current tree.
Node builder
Root node with all training records.
Split preview
Waiting
Parent impurity
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Weighted children
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Left records
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Right records
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Gain
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Balance
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Choose a feature to inspect the proposed split.
Coach feedback
Immediate guidance after every decision.
Start by finding a split that creates purer child nodes.
Challenge progress0%
Keyboard: Ctrl Z undo, Ctrl Y redo, H hint, T test.
Accessibility and display
Testing and evaluation
Measure generalisation, inspect mistakes, and compare complexity.
Plotly analytics
Explore split quality, feature importance, prediction quality, and score history.
Decision rules
Plain-language paths from root to leaves.
Achievements
Earn badges for strong, simple, generalisable trees.
Save and export
Keep progress or share the tree and results.
Local leaderboard