How to get Rubber on my steel plate product?

Hi there, I am producing steel 12" x 12" plates, and I want the top to have some rubber areas.

See this image as a crude example online:

How could I get a certain area of my 12" x 12" covered with a nice textured black rubber to provide grid for what is placed on the platform? I wouldn’t want the rubber everywhere but just in some pattern like a couple rectangles of rubber here and there - you know what I mean?

How would I even begin to do that?

Thank you