in src/lib/vpsc.js [185:195]
Block.prototype.isActiveDirectedPathBetween = function (u, v) {
if (u === v)
return true;
var i = u.cOut.length;
while (i--) {
var c = u.cOut[i];
if (c.active && this.isActiveDirectedPathBetween(c.right, v))
return true;
}
return false;
};