This redstone computer, like my previous one, is capable of running Conway's Game Of Life on an 8x8 pixel screen. However, this version is capable of running any of the 2^18 possible examples of two-dimensional cellular automata, that rely on the amount of activated neighbors of the eight that surround each cell to decide the next state for the cell. Examples of the rules it can run can be found here; http://www.conwaylife.com/wiki/Rulestring#Rules.
Each cell is 25 blocks wide, 25 blocks wide and 93 blocks high, being almost twice as tall as the cells on my previous machine. Each cell contains 2832 pieces of redstone wire, and 832 redstone torches, brining the grand total to 181,258 pieces of redstone wire and 53,248 redstone torches being present in the 8x8 pixel screen. This count does not include redstone wired or redstone torches in the other components necessary to control the computer, nor does it include the redstone repeater used throughout the computer. As described before, it is capable of being programmed with a rule that controls how a pattern that is initially set into the machine is iterated over time.

For this to occur, each cell has an 18 bit internal memory constructed of D-flip flops that are arranged to create a SIPO shift register (http://en.wikipedia.org/wiki/Shift_register#Serial-in.2C_parallel-out_.28SIPO.29). A large building on the far side of the map houses a PISO shift register (http://en.wikipedia.org/wiki/Shift_register#Parallel-in.2C_Serial-out_.28PISO.29) that holds the master program. This program can be set at will, and is transferred into each of the cells by pulsing a oprogram shift clocko, a control located in the main control room above the centre of the 8x8 matrix of cells. The lever must be pushed 18 times in order to completely copy a program from the master ROM to the internal memory in all of the cells.

Each program ,as stated above, contains 18 bits. This 18-bit binary string is set into two parts; the first 9 bits dictates in what circumstances a cell will stay active, and the next 9 dictate in what states a cell will be activated when it is inactive. For example, the binary string of the rule oWalled Citieso;
001111000000011111 means that a cell will stay active if it is already active if it has 2,3,4 or 5 active neighbors, and will activate if it is currently inactive if it has 4,5,6,7 or 8 active neighbors.

Each cell then must calculate the number of active neighbors by the use of a binary Hamming weight counter (http://tams-www.informatik.uni-hamburg.de/applets/hades/webdemos/20-arithmetic/80-bitcount/bitcount-animation.html) . Its 4-bit result is then fed into a system of logic gates connected to the cellos internal shift register, which then determines the next state the cell should occupy when instructed to do so.
Each initial pattern in the computer is set in a secondary control room, close to the master ROM. This room contains controls for each of the 8 rows and 8 columns of the screen. Another switch is then used to force activate the cells that are set by the row and column levers, hence creating a initial pattern that can be iterated.

Finally, it is important to note that while programming the machine, the immense size of the machine, which some blocks over 260 blocks away from the player, causes glitches tom often occur if care is not taken. When programming, the program shift clock must be held down for 4 seconds, to ensure it is long enough for the cells to respond too, and the user must wait 23 seconds before proceeding to the next one, to avoid creating false shift signals. When combined with regular checks with McEdit to identify any malfunctions that could hinder programming, programming usually proceeds without errors or malfunctions. Running a rule, does not require as much care, but suffers from excessive time delays, even through the use of redstone repeaters within the cells of the computer.



Another Youtube video of this creation is http://www.youtube.com/watch?v=6TPwaGNuD, showing the machine running the "Maze" rule.