after riding back from work today, i found a screw in the rear tire.
from what i've read, when running over a screw, the front tire will kick it up perfectly aligned to pierce the rear tire perpendicularly.
I sprayed it with soapy water and it showed a small leak.
I uploaded images of the leak and the tire plug i used to fix it.
it was a one inch drywall screw.
-a|ex