Now Playing: Border wall stalemate holds as government shutdown looms

Now Playing: Michael Flynn to be sentenced for lying to FBI

Now Playing: These ugly Christmas sweater nails are Pinterest-perfection and easy to pull off

Now Playing: Disney's 'Gingerbread Lady' shares tips for building the perfect gingerbread house

Now Playing: Student records '1 second of positivity' each day and the results are amazing

Now Playing: Ex-NASA engineer uses glitter to thwart package thieves

Now Playing: Police officers killed by train while chasing suspect

Now Playing: New warning issued on e-cigarettes and young people

Now Playing: Meghan Markle visits Brinsworth House, a nursing home for artists and entertainers

Now Playing: Ex-Green Beret's wife defends husband as Trump considers pardon

Now Playing: 'Fresh Prince' star sues Fortnite makers over 'Carlton' dance

Now Playing: New book sheds light on how dads can empower their daughters

Now Playing: How to protect against germs during holiday travel

Now Playing: Saoirse Ronan dishes on 'Mary Queen of Scots'

Now Playing: CBS denies Les Moonves $120M payout

Now Playing: How a hurricane-ravaged community came together to 'save Christmas' this year

Now Playing: What to know about the new test for breast milk

Now Playing: Ringo Starr joins Paul McCartney on stage for mini-Beatles reunion

Now Playing: Tips and tricks for last-minute Christmas shopping

Now Playing: New bodycam video shows dramatic moments of Las Vegas shooting