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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.
I can't understand. Why perimeter(7) should return 216? Because my code return 324, and i think its correct. Update: Why we have to multiply by 4? And why we calculate one block of one? we need calculte only 1 block of 1 but we calculate 2 blocks of 1?