An orrery is defined as an apparatus showing the relative positions and motions of bodies in the solar system by balls moved by a clockwork.
There are a few Lego orrery's out there of note the most beautiful being by V&A Steamworks
I love the idea of using the mechanical concept of the Orrery artistically.
I think Lego is actually lacking considerably in their artistic use of technic elements and I decided to challenge myself to do just that.
It took me a long bit of time to come up with something that could use the dynamic nature of the orrery but then it struck me...Quidditch!
Flow of Motion
This orrery design has 3 arenas of motion.
Prime Arm A rotates clockwise round Prime Axis (Yellow) with A3 on one end. Secondary axis on Prime Arm A rotates a secondary Arm so that A2 has an "erratic" orbit around A1. A2 orbits the secondary axis faster than A3 orbits its axis.
Prime Arm B rotates counter clockwise. Secondary Axis (which is mirrored) has a clockwise rotating Secondary Arm. B1 and B2 are equidistant from their axis so they appear to be spinning around each other WHILE spinning around the primary Axis.
There are two identical Prime Arms on the C level each terminating in C1. These arms turn clockwise. Two, non-rotating arms descend from Prime Arm B however terminating in C2. These elements Turn counter clockwise to the outer ring formed by the four C1s.
In the quidditch scenario depicted. The Snitch (A1) is being pursued by Harry (A2) while Malfoy (A3) occasionally gets close to the Snitch but never as well as Harry.
B1 is a Chaser and B2 is a Beater. They orbit the bludgers. In this depiction Gryffindor has the Quaffle.
The C1s are Chasers with and the C2s are Beaters.
I am far from done with this concept and have some interesting alternate displays planned for the future.