This is an editor of :Effect resources, which have graphs like this:

    <http://light9.bigasterisk.com/effect/effect43> a :Effect;
    rdfs:label "effect43";
    :publishAttr :strength;
    :setting <http://light9.bigasterisk.com/effect/effect43_set0> .

    <http://light9.bigasterisk.com/effect/effect43_set0> :device dev:strip1; :deviceAttr :color; :scaledValue 0.337 .

# Objects

SyncedGraph has the true data.

Effect sends/receives data from one :Effect resource in the graph. Only Effect knows that there are :setting edges in the graph. Everything else on the page
sees the effect as a list of (effect, device, deviceAttr, value) tuples. Those values are non-null. Control elements that aren't contributing the effect
(_probably_ at their zero position, but this is not always true) have a null value.

GraphToControls has a record of all the control widgets on the page, and sends/receives edits with them.

We deal in ControlValue objects, which are the union of a brightness, color, choice, etc. Some layers deal in ControlValue|null. A null value means there is no
:setting for that device+attribute

SyncedGraph and GraphToControls live as long as the web page. Effect can come and go (though there is a plan to make a separate web page url per effect, then
the Effect would live as long as the page too)