If you are looking for free ways to experience multidimensional chess or improve your skills, consider these options: 5D Chess With Multiverse Time Travel on Steam
Key concepts:
The game adds two new axes of movement—Time and Multiverse—to the standard X and Y coordinates. Multiverse Time Travel:
Victory is achieved by checkmating any of the opponent's Kings, whether they exist in the present, the past, or an alternate dimension. Key Features 5D Chess With Multiverse Time Travel on Steam
Thus, is mandatory.
Free mode is undecidable in practical terms. A single move can increase the number of boards exponentially. For (n) turns and (t) timelines, the state space is (O(64 \times n \times t \times \textpiece types)). In free mode, (t) can grow without bound.