Kepler & K2 provide long-baseline, high-precision photometry for exoplanet and astrophysics research.
The basic and most common additional rule for Doubles play is that where a Double exists at the end of any train, the Double must then be 'satisfied' (laid against) in the next turn, even if the Double is on another player's train that is not marked.
The goal of the challenge is to pass the ball around the circle, from person to person, without using your arms at all. If the ball touches the ground you must start over. A good exercise in patience! This game can also be played with everyone sitting side-by-side in a line with their legs out in front of them.