Install cairo-dock-rendering-plug-in by entering the following commands in the terminal:
sudo apt update sudo apt install cairo-dock-rendering-plug-in
Rendering plug-in for Cairo-dock
A collection of official plug-ins and applets for cairo-dock. . This plug-in adds different views to your dock. Any dock or sub-dock can be displayed with the view of your choice. Currently, 3D-plane, Caroussel, Parabolic, Rainbow, Slide, and Curve views are provided.