Project object on top of periphery of aperture

Hi there,

I need an aperture to conceal the edges of a dotstim object. This aperture creates a grey periphery to that dotstim.

My question is, is it possible to add visual stimuli on top of that grey periphery of the aperture? I would like to add a square that changes from black/white at the onset of a stimulus of interest, to be recorded by a photodiode.

Is there a way to set the depth of the aperture? Or would it possible to program a ring shape instead? I’ve tried to code a ring stimulus with and visual.polygon but the line width seems capped, preventing from creating a thick enough ring.

Thank you!

For now, I’m using a sefl contructed PNG file of a ring shape which works well.