In the main, the sigil refers to the type of the eventual value, regardless of what contains it. The tl;dr is that you mostly use `$` unless you're wanting more than one value, or to dereference (when you use the sigil for the type of reference). Some examples:

    @array = ("a", "b", "c", "d"); # @array contains scalars
    $array[0];                     # use `$` for a single element
    @array[0..2];                  # use `@` for an array slice
    @array = ( [1..5], [6..10] );  # @array now contains array references
    $array[0];                     # use `$` still because references are scalars
    $array[0][1];                  # still use `$` even when going multidimensional
    @{ $array[0] };                # use `@` to dereference an array ref to array
    %hash = ( a => "b", c => "d"); # % for hash of key/value pairs
    $hash{a};                      # `$` because you're getting a single scalar
    @hash{"a","c"};                # `@` because you're getting an array of values

    $arrayref = [1,1,2,3,5];       # `$` because we're creating an array reference
    $arrayref->[0];                # `->` because top level
    $arrayref = [ [ 1 ], [ 2 ] ];  # arrayref of arrayrefs
    $arrayref->[0][0];             # no second `->`
    $arrayref->[0]->[0];           # ... but you can use it if you want!

    $arrayref = [1,1,2,3,5];
    $arrayref->@[0..3]; # oh dear. get a real array with an `@` but not at the start!

> Where things become a bit less regular is the difference between reference and non-reference for hashes and arrays when they are top level. At the top level, you need a `->` but that becomes optional at levels below

Yes, that's probably what I was remembering. Thanks for the exposition.