$ perl -E '
    my @x = (5,1,2,3,4,5,6,7,8,9,8,7,6,5,4,3,2,1,5,9,8,5,7,5,5,5);
    say "|@$_|" for
        map [@x[$_+1 .. $_+($#x-$_ >= 3 ? 3 : $#x-$_)]],
        grep $x[$_] == 5, 0..$#x;
'
|1 2 3|
|6 7 8|
|4 3 2|
|9 8 5|
|7 5 5|
|5 5|
|5|
||

##</code><code>##

$ perl -E '
    my @x = (5,1,2,3,4,5,6,7,8,9,8,7,6,5,4,3,2,1,5,9,8,5,7,5,5,5);
    say "|@$_|" for
        map [@x[$_+1 .. $_+3]],
        grep $x[$_] == 5, 0..$#x-3;
'
|1 2 3|
|6 7 8|
|4 3 2|
|9 8 5|
|7 5 5|