It’s easy to get attached to these area bike racks

Located in Cambridge, this rack is a sleek, swept-back curve of silvery metal.David L. Ryan/Globe Staff

Bicycles have been around for 150 years. Bicycle thefts have been around nearly as long: 150 years, minus a day? So cyclists learned very quickly to lock their bikes. Bicycles and bicycle locks have evolved a great deal since. Bicycle racks? Not really. Pretty much anything solid and bolted down would do: fences, railings, signposts, and, yes, plain-vanilla (meaning simple metal) bike racks.

That’s been changing. Some bike racks have become pretty snazzy.

2284 Massachusetts Ave., Cambridge

Situated in front of a Montessori school and dentist office, this rack is a sleek, swept-back curve of silvery metal. It looks vaguely aerodynamic, as if leaning into the wind. If superheroes rode bikes, this would be where they’d lock them up. Super-gardeners, too: The rack includes a small flower box at one end.

1812 Massachusetts Ave., Cambridge

This tubular rack is located near the Porter Square T station.David L. Ryan/Globe Staff

It’s in front of an insurance office near the Porter Square T station. The rack consists of several interlocking tubes, like a giant-size, disassembled version of a puzzle ring. This gives it a distinctive look. No less important, the increased surface area makes it easy to lock up multiple bikes.

Cambridge Rindge and Latin School, 459 Broadway, Cambridge

This elegant rack is outside the Cambridge Rindge and Latin School.David L. Ryan/Globe Staff

These two stands have room for up to 16 bikes each. At both ends of each are small metals cut-outs of bicycles in silhouette. Very elegant. A different kind of elegance is owing to juxtaposition. Standard circle-and-post bike racks flank the stands, making their design stand out all the more.

Honan-Allston branch, Boston Public Library, 300 North Harvard St.

This play of circles and curves is found near the Boston Public Library's Honan-Allston branch.David L. Ryan/Globe Staff

These racks are a two-fer, a double two-fer, actually, since there’s a double set of them. Two oversize circle-and-post racks — slightly comical in appearance, thanks to their enlarged dimensions and bulbous shape — are next to a rack in the shape of, yes, a bicycle. The black metal surface somehow makes the play of circles and curves all the more pleasing.

Corner of Gordon and Cambridge streets, Brighton

Claes Oldenburg would appreciate this day brightener.David L. Ryan/Globe Staff

Imagine there rising up from the sidewalk a very large bicycle crank, gear teeth and all, that’s been painted magenta (or maybe it’s just dull pink). Do you find that hard to envision? That’s all right, since some inspired designer actually did it. Somewhere Claes Oldenburg is smiling (or at least putting on his cycling clips).

655 Mount Auburn St., Watertown

Found in Watertown, these playful racks mimic the shape of early bicycles.David L. Ryan/Globe Staff

Early bicycles with an oversize front wheel were called “boneshakers.” The three bike racks here mimic their shape. The design is amusing, apt, and functional. Each rack consists of two circles and a half-circle, an arrangement that allows for up to three bikes being locked to each. Appearance+utility=good design.