Two things to look at. First, how the font behaves across its single weight axis (100 → 1000). Second, how each letterform variant — default, ss01, ss02, ss03 — animates differently when that axis moves, and what calt does on top.
One variable axis. The headline below loops between wght 200 and 900 so you can watch the outlines morph; the staircase pins five sample weights.
Thirteen sample words — brand candidates and shape-revealing test strings — each rendered in four variants × calt on/off, all breathing on the same timeline between wght 200 and 900. Compare across a row for variant differences; compare down a column for calt's effect. The base A/D/L/M/O glyphs carry no weight-variation data, so default specimens containing only those letters barely move while ss03 does — that's part of what ss03 buys you. The sticky bar lets you drop out of auto-breathe and freeze every specimen at a specific weight for fine inspection.