Learnt something new today.
When trying to split a multi-dimensional array, one could use the *(splat) operator.
a = [[1,2],[3,4]]
b = [[5,6],[7,8]]
In order to include b into a without breaking the array, you could do the following:
a = [[1,2],[3,4], *b]
# a = [[1,2],[3,4],[5,6],[7,8]]
And that’s the magic of *splat.