You are able to extend the beacon pyramid and other beacons can use the same blocks, which can mean that the player can extend a beacon pyramid and take advantage that it only takes 216 extra minerals to add another beacon to the pyramid by putting them on all the edges on 1 side of the pyramid.

Maybe each beacon can check for any blocks that may be used to extend the pyramid. Because in this case, the beacons are only checking for the blocks that they require for use