add_trees( t(100,[l100a],
	t(90,[l90a],
		t(80,[l80a],nil,nil), 
		t(95,[l95a],nil,nil) ),
	t(110,[l110a],nil,nil)), 
		
t( 95,[l95b],
	t(90,[l90b],nil,nil),
	t(100,[l100b],nil,nil) ) ,
New
).