be explicit about assiging LoLs to @-sigiled variables

doc/Language/list.pod6

@@ -44,22 +44,33 @@ first element of a list is at index number zero:
 =head1 The @ sigil
 
 Variables in Perl 6 whose names bear the C<@> sigil are expected to
-contain some sort of list-like object.  Of course, other variables may
+contain some sort of list-like object. Of course, other variables may
 also contain these objects, but C<@>-sigiled variables always do, and
 are expected to act the part.
 
-By default, when you assign a list to an C<@>-sigiled variable, you create
-an C<Array>.  Those are described below.  If, instead you want to put an actual
+By default, when you assign a C<List> to an C<@>-sigiled variable, you create
+an C<Array>. Those are described below. If, instead you want to put an actual
 C<List> into an C<@>-sigiled variable, you can use binding with C<:=> instead.
 
     my @a := 1, 2, 3;
 
+Assigning Lists of Lists to C<@>-sigiled variables does not provide the same
+shortcut. In this case the outer List becomes the first element of the Array.
+
+    my @a = (1,2; 3,4);
+    say @a.flat;
+    # OUTPUT«((1 2) (3 4))␤»
+    @a := (1,2; 3,4);
+    say @a.flat;
+    # OUTPUT«((1 2 3 4)␤»
+
 One of the ways C<@>-sigiled variables act like lists is by always supporting
-L<positional subscripting|/language/subscripts>.  Anything bound to a C<@>-sigiled
+L<positional subscripting|/language/subscripts>. Anything bound to a C<@>-sigiled
 value must support the L<Positional|/type/Positional> role which guarantees this:
 
     my @a := 1; # Type check failed in binding; expected Positional but got Int
 
+
 =head1 Reset a List Container
 
 To remove all elements from a Positional container assign