When I was using the software I realized something missing that caught my attention. I tried to explain this below step by step with pictures which I think will contribute to developing the software.
In the first image, as we can see the arrow is pointing there is no toolbar that we can add a predesigned shape.
In the second image, as there are no tools I had to draw the shape on my own. As you can see the results are not satisfying.
In this image, I placed my idea on the menu. It's in a rectangle at where the arrow is pointing. You can see it below
After clicking number 1, we select the desired tool from the menu (number 2) that pops up and we draw the shape(square, triangle, circle) we like to the page with that tool.
I hope this idea will help the developing of Pencil2D.
GitHub link: Pencil2D
Official Website : Pencil2D