C1 · Bracket-Scode + Stata
Angle brackets evoke </>; the inset S anchors the mark to Stata. Pure code-tool semiotics — no characters, no chrome.
C2 · Bridgeagent ↔ Stata
Two anchored nodes joined by an arch — the bridge tagline made literal. Reads at favicon size.
C3 · Regressionstatistics
Axis, three observations, fitted line. Earnest econ/stats vibe in scikit-learn / R-package territory.
C4 · Coef-ploteconometrics
A coefficient / forest plot — instantly readable to economists, abstract to everyone else. Strongest signal to the actual user base.