North and South
Magnets have a magnetic north and south pole. The cool colours (green, blue, purple, and white) have their north pole facing outward, while the warm colours (red, orange, yellow, and pink) have their south pole facing outward.
Attracting and Repelling
Opposite poles attract, while like poles repel. All bars with cool colours can connect to bars with warm colours. All other combinations will repel each other.
Balls
SmartMax balls are attracted to all bars, regardless of their colour. More than 20 bars can be connected to a single ball.