Sketching a shake to cut slots in a colander

Hi all- im a new user and was hoping to get help on drawing shapes for cutting out slots. I just watched a tutorial on making a colander-great work! Was disappointed when no info on the creation of the shape used for cutting the slots was given. Can someone point me in the direction of a detailed description of how this was done?
I’m guessing it has to do with symmetry constraints, amd repeating a shape?
Sorry if this description doesn’t make sense.
I attached a screenshot of the geo shape used for the slots
Thank you for the help!!!

I haven’t seen this tutorial however a simple way to make the slots is as follows.
Extrude a thin blade and use the Pattern tool to create a circular group (40 in this example). Then Subtract the blades from the cone. Hope this helps.