default void notifyExternals(int mask) {
        for (int r = 0; r < 4; r++) {
            if ((mask & (1 << r)) != 0) {
                if (maskConnectsCorner(r)) {
                    notifyCorner(r);
                } else if (maskConnectsStraight(r)) {
                    notifyStraight(r);
                }
            }
        }
    }
Tries to locate a corner connectable part towards r and establish a connection.

@param r The rotation towards the external corner part
@return True if connection was established
core/src/main/java/mrtjp/projectred/core/part/IConnectableFacePart.java