default void notifyExternals(int mask) {
        for (int s = 0; s < 6; s++) {
            if ((mask & 1 << s) != 0) {
                if (maskConnectsOut(s)) {
                    notifyStraight(s);
                }
            }
        }
    }
Returns true if nothing is blocking a connection to an external part on side s
core/src/main/java/mrtjp/projectred/core/part/IConnectableCenterPart.java