testing active-low data-rails 
should be able to watch channels, not using acknowledes or env. 
channel	X (.data) : 0
channel	X (.data) : 0
channel	X (.data) : 1
channel	X (.data) : 1
channel	X (.data) : 0
X : .e(init:1) 1x~1of2 watch
	count: 1, unknowns: 0
X : .e(init:1) 1x~1of2 watch
	count: 0, unknowns: 0
