Two things to look at. First, how the font behaves across its motion axis (100 → 1800). Second, how each letterform variant animates differently when that axis moves, and what calt does on top. Use the font switcher above to compare Beta 10 against the final release: every specimen on this page re-renders in place.
Final release. The motion axis is renamed MOTN (was
wght) and a second axis TRCK (-90 → 0) adds font-level tracking.
ss03 is gone; the alphabet's alternates are ss01 and
ss02 only. \ now works as an invisible alternate trigger, which
is what the Text combos page tests.
Beta 10. Superseded by the final release. Its motion axis is
wght, it has no TRCK axis, and \ is an ordinary
printing backslash rather than a trigger (only Ω triggers alternates). Four
of its glyphs barely move across the axis, which is the "some characters weren't
animating" problem the final font fixes: see the motion audit.
One axis drives all the movement. The headline below loops across the full 100 → 1800 range so you can watch the outlines morph; the staircase pins seven sample values along the way. Advance widths do not change across the axis: the motion is entirely internal to the glyphs, so nothing reflows as it animates.
I, N,
T and L.ss01) move so little they read as static next to their
neighbours. The final release redraws all four.
font-feature-settings: "calt" 0: contextual swapping disabled, so you see
only what the variant column explicitly requests.
Tracking and calt: browsers drop contextual alternates by default the
moment CSS letter-spacing is non-zero, which is why naive tracking used to make
the letterforms snap back to base shapes. The fix every specimen here uses: force
font-feature-settings: "calt" 1 explicitly, which overrides that default. Drag
the CSS letter-spacing slider and watch the alternates hold.
The final font makes this moot for production work: the TRCK axis tracks the
type inside the font, where it cannot disturb the shaping stack at all. Prefer it over CSS
letter-spacing.