The next time you are at the Grocery Store, or Costco, or whichever store sells the plastic throw away cups. Check this out. According to Kegworks, the lines on a Solo (brand name) cup are measurement marks.
Did you know about the markings/measurement marks on the cups? I never knew. Do the generic ones or other brands have them too. I may have to hold them side by side and see. It may just be a Solo (brand) thing. Can't wait to check it out.
Great fun fact to know.Kegworks-- great site.
Have a safe Labor Day. I will be painting, (I hope). Projects to finish and all.