Consider line segments oriented vertically, horizontally, and either diagonally. The individual segments may be seen as stretching between an imaginary 12 and 6 o'clock; or 1:30 and 7:30; or 3 and 9; or 4:30 and 10:30. Thus give them singly or doubly a common center. By using them so - individually or dually - they can symbolize exactly 10 characters with distinction, clarity, simplicity and universality. In other words, taking one or two elements (here specific line segments) at a time from 4 elements total yields 10 possible combinations, and a fundamental representation in base ten. Do you see any application of such archetypal numeration?