wtf2.rb

irb
[14:20:42] kastner:kickstarter git:(master) $ irb
~/Development/ksr/kickstarter (main) > a = %w|a b c|
=> [
    [0] "a",
    [1] "b",
    [2] "c"
]
~/Development/ksr/kickstarter (main) > b = a
=> [
    [0] "a",
    [1] "b",
    [2] "c"
]
~/Development/ksr/kickstarter (main) > b[3]
=> nil
~/Development/ksr/kickstarter (main) > b[3] = "d"
=> "d"
~/Development/ksr/kickstarter (main) > b
=> [
    [0] "a",
    [1] "b",
    [2] "c",
    [3] "d"
]
~/Development/ksr/kickstarter (main) > a
=> [
    [0] "a",
    [1] "b",
    [2] "c",
    [3] "d"
]
~/Development/ksr/kickstarter (main) >