Animating a reverse walk along a worm
In each animation we walk on a spectre tile deflated a number of times,
the green tiles are potentially part of a worm that has a tip that can
be either internal (tip of a semi-infinite worm) or at the boundary.
A pair of black spectre tiles or three tiles forming a pair of a mystic
and a spectre move backwards along a worm from a boundary tip till the
origin of the spectre tile (Conway signature zero).
The number visible at the top-left corner displays the Conway signature
of the upper black tile.
From time to time the pair of black tiles rotate, showing the peculiar
feature of a (bi-infinite) worm allowing the reversal of all of its
tiles.
The animations at depth 6 (quite lengthy) present only a partially tiled
deflated spectre, in order to avoid having too many tiles in total leading
to a too heavy computation time.
(non-wriggly) worms
wriggly worms