[ + 1.0 ] * Sum ( h1 p2 ) * c+ ( h1 p2 ) * t ( p2 h1 )
[ + 0.25 ] * Sum ( h1 h2 p3 p4 ) * c+ ( h1 h2 p3 p4 ) * t ( p3 p4 h1 h2 )
[ + 0.5 ] * Sum ( p1 h2 p3 h4 ) * t ( p1 h2 ) * t ( p3 h4 ) * c+ ( h4 h2 p3 p1 )