You will be given various arrays, composed of numbers or strings. For this problem, the known pattern unit length is three. Write a function to determine if the supplied array is a strict repeating pattern. The array will have a length that is a multiple of three.

For example, [1 2 3 1 2 3 1 2 3] would return true since the first block ([1 2 3]) is strictly repeated through the remainder of the array. On the other hand, [1 2 3 1 2 3 2 2 3] would return false, since the last block is [2 2 3] rather than [1 2 3], as indicated by the first block.

This problem is a precursor to Problem 3069 and Problem 3070.