You have to create ranges in ascending sequence



(1..10).to_a
this will give you an empty array:
(10..1).to_a

1.	what are Ranges
2.	With the Range class, you can also create a range
3.	To create a range, use the .. operator. For example, here's how you might create the range 1 to 4:
4.	use the ... operator, which is the same thing except that the final item in the range is omitted
5.	Reference to_a from a range
6.	Reference to_a from a range in an excluded range
7.	Reference to_a from a letter-based range
8.	Variable based range

You have to create ranges in ascending sequence : Range Creation « Range « Ruby