From: Adam Prescott <mentionuse@...>
Date: 2010-09-15T05:41:05+09:00
Subject: Re: Iterate over a cartesian product.

ary.first is the first element of ary.
ary.product(one, two, ...) is the cartesian product of ary with its arguments.
ary.drop(1) is ary[1..-1], all the elements of ary but the first.
ary.product(*ary.drop(1)) passes each element of ary[1..-1] to
product() as an argument, making it equivalent to

ary.product(ary[1], ary[2], ..., ary[-1])

>
> That looks so cool I wish I knew what it does.
>
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