A Trapezoid is a Distorted 2 x 2 that can be formed from a normal
2 x 2 after any two adjacent dancers each move
a distance of one matrix position directly away from each other. EN: 10
From a 2 x 4, there are two Trapezoids. The Ends of one side work with
the Centers of the other side within a Distorted Box. EN: 20
The traffic pattern for some Trapezoid calls can be horrendous. Use
Stars as necessary and try to get to your ending position without
colliding with any other dancers. EN: 60
Calls must end on original Trapezoid footprints. Shape-changing
calls are not allowed. EN: 70