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Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Converting to int makes the * 2 + 1 operations done in integer arithmetics, which probably ends up saving a few cpu cycles.
Also prevents warnings about losing precision when implicitly converting from double to int.
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