var blockSize = 3;

var word = "cursedwizard";

var encryptedWord = new char[word.Length];

var j = 0;

var i = 0;

while (true) 

{

    encryptedWord[j++] = word[i];

    i+=blockSize;

    if (i > word.Length - 1) 

    {

        i = (i % blockSize) + 1;

        if (i == blockSize)

            break;

    }

}

System.Console.WriteLine(encryptedWord);