adding extra credit assingments
adding extra credit assingments


Former-commit-id: 0c1d203ad52dcf9a6d0f1e7ed0d2efb2829b59d0
Former-commit-id: b266a229b5d6e2e13deb252385409fb90c284acd
Former-commit-id: 9f47b3a1d41594a1bdca32a658e07222c12ce9b1
StanfordHCI/cs247,StanfordHCI/cs247,StanfordHCI/cs247