Universal cellular automaton

The rules for the universal cellular automaton are

{{_, 3, 7, 18, _}  12, {_, 5, 7 | 8, 0, _}  12, {_, 3, 10, 18, _}  16, {_, 5, 10 | 11, 0, _}  16, {_, 5, 8, 18, _}  7, {_, 5, 14, 0 | 18, _}  12, {_, _, 8, 5, _}  7, {_, _, 14, 5, _}  12, {_, 5, 11, 18, _}  10, {_, 5, 17, 0 | 18, _}  16, {_, _, x : (11 | 17), 5, _}  x - 1, {_, 0 | 9 | 18, x : (7 | 10 | 16), 3, _}  x + 1, {_, 0 | 9 | 18, 12, 3, _}  14, {_, _, 0 | 9 | 18, 7 | 10 | 12 | 16, x : (3 | 5)}  8 - x, {_, _, _, 8 | 11 | 14 | 17, x : (3 | 5)}  8 - x, {_, 13, 4, _, x : (0 | 18)}  x, {18, _, 4, _, _}  18, {_, _, 18, _, 4}  18, {0, _,4, _, _}  0, {_, _, 0, _, 4}  0, {4, _, 0 | 18, 1, _}  3, {4, _, _, _, _}  4, {_, _, 4, _, _}  9, {_, 4, 12, _, _}  7, {_, 4, 16, _, _}  10, {x : (0 | 18), _, 6, _, _}  x, {_, 2, 6, 15, x : (0 | 18)}  x, {_, 12 | 16, 6, 7, _}  0, {_, 12 | 16, 6, 10, _}  18, {_, 9, 10, 6, _}  16, {_, 9, 7, 6, _}  12, {9, 15, 6, 7, 9}  0, {9, 15, 6, 10, 9}  18, {9, _, 6, _, _}  9, {_, 6, 7, 9, 12 | 16}  12, {_, 6, 10, 9, 12 | 16}  16, {12 | 16, 6, 7, 9, _}  12, {12 | 16, 6, 10, 9, _}  16, {6, 13, _, _, _}  9, {6, _, _, _, _}  6, {_, _, 9, 13, 3}  9, {_, 9, 13, 3, _}  15, {_, _, _, 15, 3}  3, {_, 3, 15, 0 | 18, _}  13, {_, 13, 3, _, 0 | 18}  6, {x : (0 | 18), 15, 9, _, _}  x, {_, 6, 13, _, _}  15, {_, 4, 15, _, _}  13, {_, _, _, 15, 6}  6, {_, _, 2, 6, 15}  1, {_, _, 1, 6, _}  2, {_, 1, 6, _, _}  9, {_, 3, 2, _, _}  1, {3, 2, _, _, _}  3, {_, _, 3, 2, _}  3, {_, 1, 9, 1, 6}  6, {_, _, 9, 1, 6}  4, {_, 4, 2, _, _}  1, {_, _, _, _, x : (3 | 5)}  x, {_, _, 3 | 5, _, x : (0 | 18)}  x, {_, _, x : (1 | 2 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17), _, _}  x, {_, _, 18, 7 | 10, 18}  18, {_, _, 0, 7 | 10, 0}  0, {_, _, 0 | 18, _, _}  9, {_, _, x_, _, _}  x}

where the numbers correspond to the icons shown in the main text according to

The block in the initial conditions for the universal cellular automaton corresponding to a cell with color a is given by

Flatten[{Transpose[{Join[{4, 18(1 - a), 6}, Table[9, {2^{2 r + 1} - 3}]], 10 - 3 rtab}], Table[{9, 1}, {r}], 9, 13}]

where r is the range of the rule to be emulated (r = 1 for elementary rules) and rtab is the list of outcomes for that rule (starting with the outcome for {1, 1, (1) ...}). In general, there are 2^{2 r + 1} cases in the rule to be emulated; each block in the universal cellular automaton is 2 (2^{2 r + 1} + r + 1) cells wide, and each step in the rule to be emulated corresponds to (3 r + 2) 2^{2 r + 1} + 3 r² + 7 r + 3 steps in the evolution of the universal cellular automaton.