Are All Writing Systems Alike?

(image from The Topography of Language)

Just started reading an interesting article by the evolutionary biologist Marc Changizi who claims in The Topography of Language that all the world's writing systems utilize the same set of shapes because these shapes were selected for during the evolution of our visual system (or something like that). More as I digest this interesting claim.

Money quote:
Amongst both non-linguistic and linguistic signs, some visual signs are representations of the world­ e.g., cave paintings and pictograms, respectively­ and it is, of course, not surprising that these visual signs look like nature. It would be surprising, however, to find that non-pictorial visual signs look, despite first appearances, like nature. Although writing began with pictograms, there have been so many mutations to writing over the millenia that if writing still looks like nature, it must be because this property has been selectively maintained. For non-linguistic visual signs, there is not necessarily any pictorial origin as there is for writing, because amongst the earliest non-linguistic visual signs were non-pictorial decorative signs. The question we then ask is, Why are non-pictorial visual signs shaped the way they are?

HT: Stanislas Dehaene (via The Daily Dish)