A letter from Peter McBurney:
I recall your posts about the wirefrrame toys made by children in Southern Africa. I just came across this photo (which I’ve been unable to find online).
These bikes do not look like they can actually ued for human trasport, since the main body pole (the horizintal pole) would seem inadequate. I am not sure if they are steerable – the surrounding structures on the vertical pole look like they would permit steering, but perhaps this structure is cosmetic.
Photo: The New York Time, The Global Edition, Nov 22-23 2008. Tony Karumba / Agence France-Press
Making a toy bike like that requires quite a developed geometric thinking. Remarkably that such skills can be developed and pass from generation to generation in children’s subculture, without participation of adults.
Mathematics under the Microscope 
What is perhaps not clear from this image but was clear in the original photo is that the these bikes are made of wood, held together with twine or rope.
By: peter mcburney on December 6, 2008
at 6:31 pm
So, is this, a version of cargo cult that Feynman was talking about? Instead of airplanes they build bicycles? Interesting.
By: zeynel on December 6, 2008
at 9:22 pm
Is there a special term for a simile or metaphor where comparison is made between real world phenomena and something which is blatantly non-existent? “Dragons’s den”, for example — we all know what this expression means, even if dragons are non-existent. If such a term existed, it would be quite useful in response to zeynel’s comment. I’ll try to make without it.
Feynman’s famous “cargo cult” metaphor for pseudoscience (or bad science) has this out-of-the-real-world flavour: its target — bad science — is more than real but its “source” or “vehicle”, purporting to be an ethnographic observation, is of dubious origin and could easily be just a racist myth.
Wooden bikes in the photograph are not objects of “cargo cult”; they are TOYS. Unlike hardly ever existent “cargo cult”, toys are a well known and well documented anthropological phenomenon. What strikes me is that children can create toy making subcultures of surprising sophistication. I believe that hidden mathematical components of children’s subcultures should be one of the primary targets of ethnographic studies of mathematics functioning in the real world.
By: Alexandre Borovik on December 8, 2008
at 7:21 am
Cargo cults are rare, yes, but hardly nonexistent. The John Frum cult in Vanuatu, in particular has been pretty thoroughly documented.
And I don’t really see how it’s racist, either. Cargo cult thinking abounds in even Western society’s current relationship to technology. To many people, even electricity is somehow magical, and if you watch their interactions you’ll quickly discern superstitious behaviors they have learned over the years for dealing with the technologies in their daily lives. Cargo cults just take this natural tendency and distill it.
Not every observation about non-Western cultures is racism.
By: John Armstrong on December 8, 2008
at 12:47 pm