EQUILATERAL. By Ken Kalfus. Bloomsbury. 207 pages. $24.

Snooty Western imperialist foolhardiness, simmering Arabic resentment and a 19th-century delusion that Mars has canals built as a huge irrigation project by a people far more advanced than us — that disjointed triangle is the set-up for this dark, snarky satire.

A stuffy, ailing British astronomer becomes convinced that the faint blurry lines appearing on Mars in his telescope are indeed irrigation canals, and they are under construction.

He sets out to dig an equilateral triangle 300 miles to a side, fill it with pitch and set fire to it on the night of “maximum elongation,” the point when Earth is at right angles to both the sun and Mars, forming an equilateral triangle.

The flaming geometric symbol, he theorizes, will be visible on Mars and very apparently the work of an intellect that has capabilities similar to the irrigation canal builders. Martians will reply, and the intra-galactic exchange will open a New World of discovery.

So he sets up camp in a remote, waterless Egyptian desert, where sentiment seethes against the West.

He dragoons 900,000 Arab fellahin, or peasants, and puts them to work excavating this vast strip mine of a monstrosity, while he rails on about how even the slightest flaw in the resulting figure could doom the project:

“Thayer (the astronomer) has to remind the engineers of the Equilateral’s purpose and fundamental principles.

If the figure is forced to conform to the Egyptian landscape, the astronomers on Mars will be placed in the same difficult position as their colleagues on Earth: unable to convince parochial skeptics that the markings on the distant planetary surface are the work of sentient beings.

It’s the disregard of the natural landscape that proves man’s intelligence.”

You already can see where this one is going, can’t you?

Toss in a lovelorn loyal assistant jealous of a mysterious young servant girl/nursemaid and the plot gains ground quicker than the debacle of a dig ever could.

OK, so we know today the canals were an optical illusion.

But “Equilateral” rips through every bit of whole cloth of the period that Kalfus gets near, and the shreds will be a little disconcertingly familiar to a more modern observer.

Reviewer Bo Petersen is a reporter for The Post and Courier.