When I started to think
about the topic, which is far away from those I am focused for many years
(teaching Physic at Faculty of Mathematics and physics, Charles university,
Prague) I supposed the closest connection between icons and symbols and
unambiguous direction and trend in their development.
Then I found how complicated the life is.
Some icons changed to letters and then back to symbols, looking like icons (e.g. the integral symbol). Some symbols were simply developed artificially, even if we have a tendency to look for their historical roots (nabla symbol suggestive the greek musical instrument is often supposed to come from the old Greece). Some well known symbols we suppose to come from the dawn of human civilization and we all connect with the long human history (like plus sign in math) surprisingly were developed from the written latin words like et (plus is the cross on the letter t) and some appeared simply from the “hic sunt leones” area designation, like the symbol for zero (according some sources), which is finally quite close to icon.
There are many ways of the
evolution and some of them seems to be “circles”:-).