void start_local_search(double x, double y) {
    int cx = (int) round(x);
    int cy = (int) round(y);
    for (int r = 1;; r += 2) {
        int current_x = cx - r / 2;
        int current_y = cy - r / 2;
        do {
            reply_t reply = activate(current_x, current_y);
            if (!reply.blocked && epsilon_equals(reply.value, 0)) {
                cout << "found " << current_x << " " << current_y << endl;
                return;
            }
            if (current_x == cx - r / 2 && current_y < cy + r / 2) {
                current_y++;
            } else if (current_y == cy + r / 2 && current_x < cx + r / 2) {
                current_x++;
            } else if (current_x == cx + r / 2 && current_y > cy - r / 2) {
                current_y--;
            } else {
                current_x--;
            }
        } while (current_x != cx - r / 2 || current_y != cy - r / 2);
    }
}