You will be given various arrays, composed of numbers or strings, including cell arrays of 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 not necessarily have a length that is a multiple of three.

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

This problem is a follow-on to Problem 3068 and a precursor to Problem 3070.