Ran into a problem where I had already bolted down my top right corner in the place of my top left corner, so I was left with a mysterious 8x8 tile where the normal 8x8 Core tile would not fit. Welp here is the obscure solution: Get the protruding part and add it to the left side, this way, the 8x8 Core Irregular tile has 3 positive connection points and only one negative. Hope this helps someone out lol.