Lego marble runs
Wheely tiny ball contraption 2023
James advised Uncle Andrew to modify the the top of the ramp to let balls move onto the ramp more easily.
Tiny ball contraption
Based on "Genuis Lego Inventions ..." by Sarah Dees. See page 102.
Massive marble run
Marble run V2
Extra barriers were added to stop some marbles flying off at top speed.
Spiral marble run