list_node* insert(void* d, list_node* L) {
    list_node* t = (list_node*) malloc(sizeof(list_node));
    t->data = d;
    t->next = L;
    return t;
}

for(int i=0;i<3;i++){
    list_node* L = 0;
    while (more_widgets()) {
        L = insert(next_widget(), L);
    }
}