The double back flip is an insane piece of track that heavily uses a laser cutting technique known as a living hinge, which turns wood flexible and means really interesting geometries like this can be achieved!
It's a really fun piece of track to put together, and is always an eye catching and kinetic focus of the tracks that it is a part of.
Laser cut plywood
Magets, and laser cut silicon non-slip stickers (so it grips the vertical surface)
Instructional build video.
Build time: 15/20 mins
Paint brush and wood glue not included, but if you need them check my shop.