We put weights on the top of the structure loose with no paper clip or rubber band. It held 74 washers. I was surprised that it held so many weights and not too many of the big and little dictionaries.
Since it did not hold too many dictionaries we decided to change a few things. We taped the column down more tightly. We made the card structure more even on one side. That is why the dictionaries kept on falling off.
I learned that sometimes cylinders are not very strong and sometimes they can be very strong. Also I learned that you should have a flat base so it can stand still instead of it moving all the time. That is what I learned about our index card structure.