Quercetti has been making exciting marble runs and marble roller coasters for the last few generations. They are well known for their unique tracks which includes rails, spirals and funnels, which are not found on other competitors marble kits. The video below shows a typical setup of a Quercetti marble run.
Quercetti Marble Run Vortis
Quercetti Skyrail Mini Roller Coaster
Quercetti Skyrail Roller Coaster
Quercetti Skyrail Roller Coaster with Elevator
Quercetti Skyrail Suspension Roller Coaster
Quercetti Super Marble Run Vortis
Quercetti Transparent Marble Run