)+")").call(d3.axisBottom(d));
	m=d3.histogram().domain(c_u.domain()).thresholds(c_u.ticks(100)).value(function(b){return b}),
	    g=d3.nest().key(function(b){return b.z_}).rollup(function(b){input=b.map(function(b){return b.y_});return bins=m(input)}).entries(data_u),
		f=0;for(i in g)allBins=g[i].value,lengths=allBins.map(function(b){return b.length}),longuest=d3.max(lengths),longuest>f&&(f=longuest);
	l=d3.scaleLinear().range([0,d.bandwidth()]).domain([-f,f]),n_u=d3.scaleQuantile().domain(dt_u).range(co