Is your marble run one stable sculpture?
Is it stable?
Have you met all of the criteria?
Check your craftsmanship. Are there glue drips, messy edges, rough edges, messy tape edges? All of this will take away from the aesthetically pleasing part of your marble run.
Does your marble run function?
Does your marble run use on or more marble?
Do you have a place to catch the marbles at the end?
Can you move your sculpture all as one?
Edit your sculpture as necessary and document any edits of changes that you now need to make. This is part of the process.
You now have the challenge of deciding how your group would like to " finish your sculpture". Would you like to paint it of leave it as is? It is important to make sure that you do not distract or detract from the main event- the marble running it's course. You DO NOT want to add embellishments that take away from this. Bright colors and " accessories" can do this - remember less is more.