This is one of those spur of the moment activities that turned out to be so beneficial! I lined up B’s bowling pins (you could use any group of objects) and said “Point to the one that is in BETWEEN the green and yellow pins” or “Point to the pin that is in BETWEEN the blue and orange pins”. This listening activity also strengthened his vocabulary and reviewed the colors. It was more difficult for him than I thought it would be.
For younger toddlers:
Have them point to identify the color (maybe start with 2 or 3 objects).
For older preschoolers:
Add an additional clue such as (using top picture) “Show me the pin that is in between the blue and the yellow, but is not orange.”