Complex Commonwealth Commute


Project outline

Our project was to produce a stop-motion film in which we introduced an application of a mathematical process to solve a problem. To do this we had to design props using laser cutting and 3D printing with tinkercad, use SAM for stop-motion animation, and write the lyrics to a rap that we recorded and played through our video. 

Planning Our Educational Concept

We started by trying to figure out what we wanted to make a video about. We wanted to touch upon a Combinatorial Mathematical Concept so we talked about conditional probability and Simpson's Paradox until we came up with Path Walking which could more easily be applied into a story. In our story a student who lives far away is a freshman at a new school in the center of Boston called Commonwealth. He can either take the Uber or walk from the Back Bay train station. The Uber will go directly to the school, but if he walks he either end up at Ben and Jerry's on the way or go to a deadly intersection where he will be hit by a car. This student then counts the possiblities of randomly going through each place to decide whether he should take the Uber of take the commuter train. 

Planning our Props

For our props we ended up incorporating laser cutting and 3D printing. For 3D printing we used tinkercad to design and print out our Commonwealth student and to print out the ice cream cone. We used laser cutting to cut out our representation of the commuter rail being the T symbol. For other background images such as the city, our school, and Ben and Jerry's we found some online images that we used as our background when using SAM animation to do our stop-motion animation. 

We solidified our planning by designing a storyboard which prepared what sotry we were going to do. 

3D Printing our Props

This was our first time 3D printing and we used tinkercad to design our person. It was not to difficult, and we were able to successfully make a figure with our school's Mermaid on it to print out. Our print took around 5 hours but we were fairly successful. The only difficult part was taking out the person's back which we broke, but we fixed it with some tape. We designed the ice cream cone for the end to have a ball joint to go into a socket so that it could be carried securly. 

Laser Cutting

We used laser cutting to cut out our T symbol. We designed it and let our T be rastored and the rest be etched to get a circle with a T in it. It was pretty cool, and we luckily were successful our first time. 


We used SAM animation to film with the props that we created. It was much more challenging than everything else as we had to create many frames and be very precise with them. We just followed along with our storyboard, but had some difficulty in positioning shots the way we wanted. However, we were eventually able to either change our storyboard to have easier shots, or get the camera in a good position for capturing each scene.




Commonwealth Commutes Script
January 2016

Tarang Saluja
Alex Lehner

I’m a freshman who’s never been to the city before
and I want to get to the Commonwealth front door

I don’t know whether I should just take the Uber
or whether I should just walk from the commuter

I know there is a Ben and Jerry’s on the way
but I also might get hit by a car today

To get from Back Bay to the ice cream store
There are 3 choose 2 ways and not any more

To get from the ice cream store to the school
There are just 4 choose 1 ways - that’s cool

We multiply these cases to find the count
It seems like 12 is our total amount

To get from Back Bay to the deadly intersection
5 choose 1 ways to become a victim of natural selection

To get from the intersection to the school
There is just 1 way - don’t be a fool

We multiply these cases to find the count
It seems like 5 is our total amount

There are a total of 7 choose 4 ways
I think I figured out the risks in this maze

Please note that 12 is greater than 5
 have a pretty good chance of staying alive

Alright everyone I’ll go and walk
I’m pretty glad we had this mathematical talk