The Russian embassy in Washington DC has a façade that is mostly large, flat and white. It is a design that, however accidentally, gives the building some resemblance to a projector screen.

That is exactly how it has been used by pro-Ukrainian pranksters. A video uploaded to social media this morning shows Boris Nemtsov Plaza, home of the embassy, at night-time. Onto the thick foliage of the trees to the embassy’s right is projected the Ukrainian flag, vivid blue and yellow against a dark backdrop.

The flag, apparently beamed from the other side of the wide avenue, begins to tack to the left. Inexorably it moves towards the Russian embassy, arriving at the top-left corner. The embassy is already lit by large, faint spotlights in the red, white and blue of Russia’s flag – and by a second, weaker Ukrainian flag, suggesting some prankster coordination.

It is the stronger flag that prompts the interception attempt that has made this video go viral. Up sweeps a white Russian spotlight, straight to the incoming Ukrainian flag. “They’re trying to drown you out,” comments an onlooker.

The attempted military escort is thwarted. The Ukrainian flag is so bright that the white spotlight hardly shows up. Emboldened, the Ukrainian flag makes a further incursion into Russian territory, adding insult to injury by provocatively bobbing up and down.

The Ukrainian flag is showboating by now, dominating the white façade. When the Russian spotlight pursues it, the Ukrainian flag jiggles away. The 43-second clip ends with audible laughter.