Safe harbors and mysterious bikes

Yesterday, I had to take Frida deep into East Cambridge for the first time.  She was kind of freaked out about being left by herself outside in a strange new setting after spending so much of her young life within the rarefied bounds of Harvard Yard, so I did a quick survey of available parking options and sought out the safest-looking, most populated among them.  There was a a nice little pedestrian way leading off the street that was well stocked with bicycle racks and bicycles, so I wheeled Frida over to one of the rearmost racks, which also had the most Frida-friendly bikes attached to it.

Here you can see she is being kept company by a cruiser-style mixte (more on this in a bit), a men's KHS Green (which immediately calmed her down!), and a very dapper charcoal and honey diamond frame bike whose saddle and handlebar tape matched Frida's handbag perfectly.  Here she is snuggling up close to his reassuring and color-coordinating figure:

Not only was his casual handsomeness soothing, but there was also this:

See, Frida?  Chillax already!

Now, the mixte [Q: is it still a mixte if the top tubes don't connect directly to the rear axle?].  This was a strange one.

We've got: wide, almost Dutch-style handlebars; a twin-tube mixte frame with a delicate yet cruiser-ish swoop; huge, super-nubby mountain bike-type tires, with one fender on the front tire only; a vaguely 1950s-feeling partial chain guard; some kind of crazy, giant spring thing by the front rack; and nary an identifying mark to be found.  What to make of this idiosyncratic fellow?  I really didn't know, but I left him a note before heading inside:

Part 1 of the Let's Go Ride a Bike Summer Games: Social Cycling>> leave a friendly note on a bike.

(I was taking these with the camera on my phone, so I'm just going to call the reverse focus on the last one "artsy.")

When I got back, it was dark, the mixte and diamond frame were gone, and Frida was sitting there quietly and calmly, ready to head home after a long but pleasant day.