@@ -97,32 +97,17 @@
    @Override
    public void onPlace(BlockState state, Level level, BlockPos pos, BlockState oldState, boolean movedByPiston) {
        super.onPlace(state, level, pos, oldState, movedByPiston);
        System.out.println("[AlacrittyMC] onPlace at " + pos + " side=" + (level.isClientSide() ? "CLIENT" : "SERVER"));
        BlockEntity be = level.getBlockEntity(pos);
        if (be instanceof TerminalBlockEntity terminalBE) {
            terminalBE.rescanGroup();
            System.out.println("[AlacrittyMC]   self rescan: group=" + (terminalBE.getScreenGroup() != null
                    ? terminalBE.getScreenGroup().getGridCols() + "x" + terminalBE.getScreenGroup().getGridRows()
                    : "none") + " ext=" + terminalBE.isExtension() + " cols=" + terminalBE.getCols());
        } else {
            System.out.println("[AlacrittyMC]   NO block entity at " + pos);
        // Rescan this block only — neighbors will pick up changes via lazy client tick.
        // Don't cascade rescans here: it causes O(n²) work and can interact badly
        // with world modification during block placement.
        try {
            BlockEntity be = level.getBlockEntity(pos);
            if (be instanceof TerminalBlockEntity terminalBE) {
                terminalBE.rescanGroup();
        }
        int neighborCount = 0;
        for (Direction dir : new Direction[]{Direction.NORTH, Direction.SOUTH, Direction.EAST, Direction.WEST, Direction.UP, Direction.DOWN}) {
            BlockPos neighbor = pos.relative(dir);
            BlockEntity neighborBE = level.getBlockEntity(neighbor);
            if (neighborBE instanceof TerminalBlockEntity neighborTBE) {
                neighborTBE.rescanGroup();
                neighborCount++;
                System.out.println("[AlacrittyMC]   neighbor " + dir + " at " + neighbor
                        + ": group=" + (neighborTBE.getScreenGroup() != null
                        ? neighborTBE.getScreenGroup().getGridCols() + "x" + neighborTBE.getScreenGroup().getGridRows()
                        : "none") + " ext=" + neighborTBE.isExtension() + " cols=" + neighborTBE.getCols());
            }
        } catch (Exception e) {
            System.err.println("[AlacrittyMC] Error in onPlace rescan: " + e);
        }
        System.out.println("[AlacrittyMC]   " + neighborCount + " terminal neighbors found");
    }
    @Override

@@ -237,27 +237,41 @@
    /**
     * Called when this block is broken. Stops terminal, notifies neighbors.
     * All operations are wrapped in try-catch to prevent crashes from
     * cascading group updates during world modification.
     */
    public void onBlockRemoved() {
        try {
            stopTerminal();
        } catch (Exception e) {
        stopTerminal();
            System.err.println("[AlacrittyMC] Error stopping terminal: " + e);
        }
        // Capture and clear group state BEFORE notifying neighbors
        ScreenGroup group = this.screenGroup;
        this.screenGroup = null;
        this.controllerPos = null;
        // Notify remaining group members — clear their stale refs and let
        // Notify remaining group members to reform without this block
        // the lazy client tick rescan later (don't do cascading rescans now,
        // as the world state may be inconsistent during block breaking)
        if (level != null && group != null) {
            for (BlockPos memberPos : group.getMembers()) {
                if (memberPos.equals(getBlockPos())) continue;
                BlockEntity be = level.getBlockEntity(memberPos);
                if (be instanceof TerminalBlockEntity member) {
                    // Clear stale group references first
                    member.screenGroup = null;
                    member.controllerPos = null;
                    member.clientGroupScanned = false;
                    // Then rescan to form new group(s) without the broken block
                    member.rescanGroup();
                try {
                    BlockEntity be = level.getBlockEntity(memberPos);
                    if (be instanceof TerminalBlockEntity member) {
                        // Clear stale refs — lazy tick will rescan
                        member.screenGroup = null;
                        member.controllerPos = null;
                        member.clientGroupScanned = false;
                        member.clientTickCount = 0;
                        // If this member was running a terminal (it was
                        // the controller), the terminal is now orphaned.
                        // Don't stop it here — let the rescan handle it.
                    }
                } catch (Exception e) {
                    System.err.println("[AlacrittyMC] Error notifying neighbor at " + memberPos + ": " + e);
                }
            }
        }