Alex from Vancouver, British Columbia, presents his amazing prosthetic the "Robotic Hand." Mike from North Bay, Ontario, presents the "Ice Ace," a portable Zamboni everyone can use. Led by Alex, Team DaVinci squares off against Mike and Team Newton to see who can create the best motorized Dust Bunny in the Invent-off Challenge. But first, the teams build the chairs out of cardboard and cable ties in the Cable Tie Chair mini challenge.