Explanation for -1):
For an example of (2) identical fabrics see Fig. -3(e).

These fabrics are identical because
all the "corresponding crossings" are identical.
(A typical group of corresponding crossings
has been designated by the marker-circles.)

The crossings in that group are identical because
in both crossings
the "a"-element crosses past the "b"-element in the same way,
whether over - as shown - or under.

Explanation for -2):
Each "node" in the structure
looks like the node shown in Fig. -3(c),
when seen from the proper direction.
(As shown, a node is
a crossing where (3) mutually perpendicular elements
touch and pass each other.)

The node in that fig. is a right-handed node, because
it can be regarded as an incipient right-handed twist.

Thus, all the nodes in the structure are right-handed nodes,
and therefore the structure is a right-handed structure.

The fact that all the nodes in the structure are right-handed
is shown schematically in Fig. -3(d).

That diagram shows all the nodes,
as embedded in the vertical stack.
Each node is represented by a small cube,
designated "L" & color-coded orange,
or
designated "R" & color-coded blue,
to represent a
left- or right-handed node respectively.