In macirb the following code crashes

>> array = NSMutableArray.arrayWithObjects([1,2])
=> [[1, 2], 1511869]
>> array
=> [[1, 2], 1511869]
>> array.length
=> 2
>> array2 = NSMutableArray.arrayWithObjects([1, 2, "this"])
Killed

Using the more ruby friendly way of assigning a variable to an array works.

>> array = [1,2,"this"]
=>[1, 2, "this"]