Let The Races Begin, With This Amazing Marble Run Roller Coaster! It's So Simple To Build: Just Press Out The Model Pieces, Assemble The Marble Run Using Glue Or Adhesive Tape, And You'Re Ready To Go. The Track Has A Switcher And Two Funnels—plus A Gravity-Defying Loop-The-loop, Fun Steps, And Amazing Slopes—so The Winning Marble Will Always Be A Surprise. The Base Of The Book Becomes A Secure Stand For Your Model, And You Get Easy-To-understand Explanations Of The Physics And Engineering Involved.