Phantom Domino at Gresham and Kingshighway?

A few weeks ago I was out running, jammin' to a smoove mix of Isley Brothers and The Spinners, when I happened to look down as I crossed over Gresham. Being a sunny day, the shadows pointed out a subtlety in the (new?) pavement. I doubt I would have noticed this while on the bike, so it must have been destined by the gods atop Mount Olympus. I am reasonably sure there was recently two dominoes in a "T" formation until they were either removed or knocked out.

This location is in a veritable hotbed of pavement domino activity, and the size and depth of of the impression is spot-on for 2 dominoes like the ones I've already come across. I'm going to add this to my list of locations with a Barry Bonds-style asterisk next to it.

Were they removed on purpose? Is there a clashing faction of anti-domino activists working to rid the city of this mystery? Perhaps it is an inside job within the group who is installing them in the first place - someone who has seen my blog here and is trying to erase all the evidence - me included! Oh man, shit is about to get real. I better go buy some grenades.