private void Start()
    {
        build_manager.AddMapChangedListener(() => RefreshUI());
        RefreshUI();

        entrance_button.onClick.AddListener(() => build_manager.place_blocks.SetSelectedToEntrancePiece());
        exit_button.onClick.AddListener(() => build_manager.place_blocks.SetSelectedToExitPiece());
    }
 private void Start()
 {
     build_manager.AddMapChangedListener(() => RefreshUI());
     RefreshUI();
 }
 private void Start()
 {
     build_manager.AddMapChangedListener(() => RefreshUI());
     clear_button.onClick.AddListener(() => build_manager.ClearLinks());
     RefreshUI();
 }