For some presentation slides, you might need a calendar as a background picture. For example, when you want to present some events or processes. Sure, there are a lot of existing templates that you can use, but it is easy to create your own calendar from scratch.

Often you see the elements of the slide like the company logo, copyright notice, or background picture, which you can't change or remove because they are part of the company template and seem to be read-only. However, the secret is that if you open the Slide Master, you can change every element of the slide.