Visualizations Show ASCII Instead of Diagrams

Data structure visualizations print as ASCII text instead of diagrams when the system Graphviz binary is missing. Install Graphviz and restart the terminal.

No error is raised. Visualization objects print as ASCII fallback text instead of rendered diagrams, which means the system Graphviz binary is missing. The Python package alone is not enough: rendering shells out to the dot executable.

​

Fix

Install Graphviz for your platform (download guide):

brew install graphviz      # macOS
sudo apt install graphviz  # Debian/Ubuntu

Restart the terminal afterwards so the new binary is on PATH, then re-run the notebook or script. What the rendered output looks like is shown in Visualizations.

Not this problem? Every fix lives on Troubleshooting.