Making custom apertures by combining existing Apertures

It's rather a question...

I wanted to make a pillbox-shaped aperture, as in TRIPPY (e.g., [here](https://nbviewer.jupyter.org/github/fraserw/trippy/blob/master/tutorial/trippytutorial.ipynb)), because all the stars in my images are trailed (due to the non-sidereal tracking mode).

I thought it will be easy enough because what I have to do is just combining two circles with a rectangle (overlapping regions will not matter much if I use ``mask`` properly) using ``photutils``. But currently I am stuck at the very first step... I can't just sum or combine the apertures as I sometimes do for astropy models. I think there should be simple workaround, but couldn't figure out so far.

Do you have any idea?

Start with the linked TRIPPY tutorial and photutils' existing Aperture classes; inspect how their masks are produced and whether the current API supports combining shapes. Done means documenting or enabling a supported way to construct a pillbox-shaped aperture from two circles and a rectangle, with overlapping regions handled as intended.

Written by the indexing model from the issue text.