Very nice. Minor shortening to:

@arr [@arr - $o .. $#arr, 0 .. $#arr - $o]
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Using the % trick, you might try this instead:

@arr [map $_ % @arr, @arr - $o .. @arr - $o + $#arr]

or:

my $p = @arr - $o; @arr [map $p++ % @arr, @arr]
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So your slice looks a bit better.