For those of us who have been intoxicated by the powers and possibilities of mathematics, the mystery isn’t why that fascination developed but why it isn’t universal. How can students not be entranced? So profound are the effects of math for those who have felt them, that you never really become a former mathematician (or ex-mathematics student) but one who has “lapsed,” as if it were an apostasy.

So why, until now, has there apparently been no major museum of mathematics in the United States? Why, when so many identities and advocacies have representation in the museological pantheon, has math been so neglected? Here and there, perhaps, a hobbyist has displayed puzzles, and our gargantuan science centers occasionally deem it worth their while to descend into algebraic abstraction. But a museum devoted to math? You have to immerse yourself in the history of science museums in Europe — where math sits at the foundation of things — to get an inkling of what it might mean.

Or, for an entirely different experience, you can go to Madison Square Park in Manhattan to see the new Museum of Mathematics, which opens on Saturday. It refers to itself as MoMath (and since it is near MoSex — the Museum of Sex — that means we now have a museum district explicitly evoking the mind-body problem).

MoMath is not what you might expect. At first you might not even guess its subject. There are a few giveaways, particularly if you recognize the symbol for pi on the door or discover the pentagonal sinks in the bathrooms. But what is that cylinder constructed of plastic tubes stretching toward the ceiling with a seat inside (“Hyper Hyperboloid”)? Or that transparent wagon that slips along multicolored acorns in a trough (“Coaster Rollers”)? Or a tricycle with three square wheels, each of a different size, rolling along a bumpy circular track (“Square-Wheeled Trike”)?