A challenge for the housebound: make a complex soap machine

The ball drops, the train goes for a ride, the rabbit takes a zip-line, the balls hit the floor, triggering this mechanical spider, which turns on the shower, spraying water and knocking the bar of soap into 11-year-old Caitlin Diel's hands the hands.

Welcome to the Rube Goldberg challenge, lockdown edition.

Named for Pulitzer Prize-winning cartoonist, who drew overly complex, zany inventions, the non-profit Rube Goldberg Inc every year takes submissions for chain reaction machines that perform simple tasks.

And with everyone stuck inside and constantly reminded to wash their hands, this year's contest was to deliver a bar of soap.

Jennifer George is the late cartoonist's granddaughter and director of Rube Goldberg Inc.

"We wanted something that was sort of relevant to what's going on today and we want to make sure people are washing their hands."

She partnered with the skincare company Beekman 1802. They shot this video, using their bars of soap like dominoes.

Dr. Brent Ridge is one of 1802's co-founders.

"We're so excited to partner with the Rube Goldberg organization on their latest contest, how to deliver a bar of soap into someone's hands. Now, all you have to do is using things that you have around your home, build a Rube Goldberg contraption that delivers a bar soap into someone's hands."

The Diel family and their three kids built their Rube Goldberg machine in the family bathroom. And getting it to work only took 6 hours and over a hundred attempts.

And 7-year-old Madeline Diel said the activity took away some of the anxiety around why they're stuck at home.

"This was meant to be like not to make you scared, but to make you happy. And over the thousand times it failed... It was lots of things, but every time we were like, 'we can do it', and that's what it's really about."

The contest has drawn at least 225 submissions from more than 33 states, cities as far away as Liverpool, England, and countries as distant as Mozambique. Winners are set to be announced on June 7.