Having never played dominos (I was thinking of lining them all up then knocking them all down in sequence when i read the title), I was confused at first lol.
I really like the idea of a visual editor and visual connections, like a node-based graph. As of now, I see points that match. yet they won't align.
PT gui shows the connections with lines I believe. I would love a more intuitive "guided" align than the marker system, because it just doesn't always work.