Node aw attributes:
Node bw attributes:
Node cw attributes: ignore_weak_interference
	0	aw : 1
	0	bw : 1
	10	cw : 0	[by bw:=1]
now interfere! 
should have no diagnostic 
WARNING: interference `cw'
>> cause: `aw' (val: 0)
	10	aw : 0
	20	cw : X	[by aw:=0]
remove interference... 
	20	aw : 1
	30	cw : 0	[by aw:=1]
now weak interference... 
	30	aw : X
	40	cw : X	[by aw:=X]
remove interference... 
	40	aw : 1
	50	cw : 0	[by aw:=1]
flip side... 
	50	bw : 0
	50	aw : 0
	60	cw : 1	[by aw:=0]
interfere pull-down 
but message should be suppressed... 
WARNING: interference `cw'
>> cause: `bw' (val: 1)
	60	bw : 1
	70	cw : X	[by bw:=1]
remove interference... 
	70	bw : 0
	80	cw : 1	[by bw:=0]
now weak interference... 
	80	bw : X
	90	cw : X	[by bw:=X]
remove interference... 
	90	bw : 0
	100	cw : 1	[by bw:=0]
both off... 
	100	aw : 1
X-pull-up 
	100	aw : X
	100	aw : 1
X-pull-down 
	100	bw : X
	110	cw : X	[by bw:=X]
	110	bw : 0
X vs. X 
	110	aw : X
	110	bw : X
more weak interference... 
	110	aw : 0
	110	aw : X
more weak interference... 
	110	bw : 1
	110	bw : X
