power of visual communication  

perhaps consider grass...
perhaps consider grass movements, propaganda, as areas where visual communication was/is used to illicit response, confront.

2D to promote 3D
Try an experiment: -The design blind test-
Find a large enough room which can be endarkened,
Select a selection of an half dozen of famous design items, and another half dozen furnitures, and item issued from local artcraft, or industrial patented items.
Mix the all things in this room.When the presentation is all set, ask volunteers to enter the dark room with a headscarf around their eyes. Make sure they feel blind first and ask them to identify as much design items as they feel, while snooping around the darkroom. Collect the informations data after they leaved the room. Compare to real items, dress figures and debate.... Could be a pretty interactive activity to introduce visual communication.

this is tactile sensory...
this is tactile sensory perception, and
not visual communication, as ones visual perception would be impaired by the headscarf.

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READ:How to see by G.Nelson.

to azurechicken
The idea was to feel the items in order to determine if wether or not, one can imagine what they look like on a visual angle. The question asked, was about the power of visual communication towards design. We actually live in a visual communication world (internet is a good example), but how can you distinguish a good design chair from a bad one just by looking at a picture of it, even if it would have been shot by a Kertesz, or an helmut Newton? Best thing is to experience the sitting in this chair, it's shape, line and so forth...
On the other hand, if you just want to focalize on the strictly visual communication, the topic of design would be in my opinion undetermined by the rules of graphic and aesthetic representation of the medium that holds the image. Visual communication is a big enhancer for design. In our archaïc part of brain we first see the shape of the other (ennemy or woman), before we figure out if we intend to fight or seduce the person. Visual communication has to deal with the Platon's cavern myth .That's the shadows of our imagination that can boost our endorphins. (just a point of view)

to the Plagiarist
erratum: the answer was adressed to the Plagiarist,i hope that azurechicken will forgive me.