Trapezoid Universal



1 to 2 => 2 to 1 => 2 to 4 => 4 to 2 => 1 to 3 => 3 to 1 => 3 to 4 => 4 to 3 => 4 to 1
3 to 2 =>
1 to 4
2 to 3 =>
Start with bias Start no bias