The Articles of Confederation are individual ingredients in a kitchen with the Constitution being a meal.
The Articles of Confederation had pieces of it that were worthwhile but most of the document was disconnected and good in theory but didn't come together. This is similar to all of the food in a kitchen. The food is all good and could be useful but most of it would be better when combined with other food to create a meal.
The Constitution creates a meal. It took some of the food in the kitchen and brought it together to create dishes that could be enjoyed. The good individual pieces from the Articles were kept and carried into the Constitution making the elements even better when joined with the overall meal like a roll being added as a side dish instead of being a meal by itself.