“3D Thinking” Page 15. Evolution of signs towards symbols from 70,000 to 5,000 years ago – where the European ice age ended around 14,000 years ago. We see directional lines that criss-cross to form triangular shapes, shapes composed of directional lines that appear rectangular, linear arrangements of dots, ‘bell’ like enclosed shapes, feather like forms, comb like forms with various quantities of attached lines, a horse, spirals composed of dots, a composition of interconnected shapes, circular and curved shapes, curved triangles, a labyrinth, concentric circles (with carved bowls), symmetry spirals and lines. pattern repeats and spirals, zig-zag repeats, concentric arch-like line repeats.