All combinations of arrays with Array#product
If you need the equivalent of a SQL cross join in Ruby check out the Array#product method.
[1] pry(main)> [1,2,3].product(%i[a b c])
=> [[1, :a], [1, :b], [1, :c], [2, :a], [2, :b], [2, :c], [3, :a], [3, :b], [3, :c]]
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