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A reversible cellular automaton using Fredkin's construction. Fredkin automaton.
A 6-state solution to the firing squad problem due to Mazoyer. Mazoyer firing-squad.
A binary width 7 cellular automaton that tests majority (with high probability). Fredkin automaton.
The first 800 steps of the Marxen-Buntrock 5-state busy beaver machine. Marxen-Buntrock automaton.
Phasespace of elementary CA 150 on 9-bit configurations, cyclic boundary conditions. Phasespace of ECA 150.
Phasespace of elementary CA 52 on 9-bit configurations, cyclic boundary conditions. Phasespace of ECA 52.
A Sierpinski triangle generated by translating [3]^8 into coordinates via the substitution 1 -> (0,0), 2 -> (0.5,1), 3 -> (1,0.2). Sierpinski substitution.
An optimal solution in the 5-disk Towers of Hanoi problem. Towers of Hanoi.
The classical bijection from N x N to N using a quadratic polynomial. Polynomial bijection.
A bijection from N x N to N based on two quadratic polynomials. Polynomial bijection.
Bitwise xor of all 6-bit numbers. Bitwise xor.
Up to 6 moves of a knight on an 8 by 8 chessboard. Knight moves.
An odd-parity cover for the 100 by 100 grid graph. Odd-parity cover.
The involution f(x) = x + 1 acting on the Fibonacci rank of appearance of all irrdeducible polynomial of degree 8 over GF(2). Fibonacci rap.
The divisor lattice of 148176 and the Hasse diagram (as Boolean matrices). Divisor lattice.
The Hasse diagram of the divisor lattice of 148176 as a directed acyclic graph. Divisor lattice.
The von Neumann ordinal 5 in tree representation. von Neumann ordinal.
The von Neumann ordinal 5 in DAG representation with shared subexpressions. von Neumann ordinal.
A slightly nondeterministic finite state machine due to Moore that demonstrates full exponential blow-up during deterministic simulation. A Moore automaton.
A slightly nondeterministic finite state machine based on a circulant graph that demonstrates full exponential blow-up during deterministic simulation. A circulant automaton.
A highly nondeterministic finite state machine due to Jiraskova that demonstrates full exponential blow-up during deterministic simulation. A Jiraskova automaton.
The canonical DFA for the dihedral group D_4. The canonical DFA for D_4.
The canonical DFA for all even permutations over 4 letters. Canonical DFA for even 4-permutations.
Acceptance of all 180 minimal (6,1)-DFAs on words up to length 60. Minimal (6,1)-DFAs.
The dihedral group D_6 acting on binary lists. Dihedral group.
The alternating group A_6 acting on binary lists. Alternating group.
The stopping times for the first 2048 values of the Collatz function. Collatz stopping times.
The up/down counts of the Collatz function for the first 100 powers of 3. Collatz powers of 3.
Lagrange interpolation of a few integral grid points. Lagrange interpolation.
A chaotic orbit of a transcendental point under a simple tent map. Tent chaos.
500 steps of a 50-bit discrete version of the logistic function with parameter value 3.56. Discrete logistic map.
The basin of attraction of 1 with respect to squaring modulo 32. Squaring modulo 32.
The relation associating squares and squares of successors modulo 512. Successor squares modulo 512.
Redundancy of 10-digit hyper-binary representations. Knuth-Calkin.
Evolution of a one-dimensional sandpile. On-dimensional sandpile.
The full transformation semigroup on three points. Each transformation is iterated 5 times. Transformation semigroup on 3 points.
The Devil's Staircase: a monotonic function no the unit interval such that f(0) = 0, f(1-x) = 1 - f(x) and f(x/3) = f(x)/2. Devil's staircase.
A bizarre surjection from the integers to the rationals: With[ {nn = Ceiling[Sqrt[n]]}, If[ n <= (nn-1)^2 + nn, nn/(n - (nn-1)^2), (nn^2 - n + 1)/nn ]] Wild surjection.
The Farey sequence and Ford circles. Farey and Ford.
The first 250 points in the backward and forward orbit of 8 under Conway's T function (log-lin plot). Conway's T function.
The number of predecessors under the operation f(n) = n/2 using ceilings and floors. Iterating the 1/2 operator.
A geometric proof of a summation identity involving binomials. Binomial summation identity.
Enumerating Chomp configurations. Chomp configurations.
Iterating riffle shuffle. Riffle shuffle.
Domino tilings equivalent under rotation and reflection. Domino tiling isomorphs.
4-colored necklaces of length 5. (5,4)-necklaces.
A curve generated by a stack turtle. Stack turtle.
A fractal rug generated by a stack turtle. Stack turtle rug.
5 elastic particles bouncing between two fixed walls. Bouncing particles.