'Photons' move around on an infinite checkerboard. Mirrors and 'junction/splitter' elements control the flow of the photons. Red and yellow mirrors change their orientation when hit.
We will see that we can build all parts of a computer from these elements, and that in fact THE JUNCTION/SPLITTER ELEMENTS ARE THE ONLY ONES WE REALLY NEED! (See below and variants for details on this fact.)

The default variant shows how such a setup can be used to create a binary counter: The mirrors on red background represent the binary digit Zero, the mirrors on yellow background the binary digit One. Hit the run button to see how the setup counts in binary: 0000, 0001, 0010, 0011, 0100, 0101... (Read the numbers when the photon is back on the bottom line).
Note: In variants with more than one photon, the run button has to be green to read the results properly! It will turn green regularly.

To drop a photon or edit the board, click one of the icons on the right. The associated letters will remind you of what the icons mean:
P : photon (default: facing north). Click board several times to make it change direction. If two photons collide on an empty position, they eliminate each other. If two photons collide on an occupied position, only one will survive.
D : mirror sloping DOWN
U : mirror sloping UP
F : mirror flips when hit by a photon from sloping up to sloping down and vice versa.
J : Junction/Splitter : Incoming photons are guided into direction of the arrow; however, photons traveling towards the arrow will be split, one to each side.
B : The BLOCK captures a photon.
D : The DELAY stops the photon for one tick.
C : CLEAR a position.

These gadgets can be dropped one by one (option 'point') or in a line (option 'line'). Use option 'shift' to move icons around on the board.
When you are finished editing the board, hit one of the run buttons.

The variants show applications of the photonworld system. For more information read the game description of the variants.

The Photonworld presented here is a new system of elements which allows us to build all components of a computer. With ease we can build all logical gates and many other machines simply from fixed (!) mirrors, junctions and splitters.

The pair of flip-flop mirrors usually can be made redundant (for example for 8-cycle data) and be replaced by a more complicated setup of junction/splitter elements. This is demonstrated in some of the variants. The flip-flop mirrors are very convenient, however, to keep constructions simple. Moreover, all fixed mirrors can be replaced by junction/splitter elements (the construction may be have to be changed, though).

Blocks are redundant since a block can be constructed using a junction and three mirrors. Delays are necessary for odd types of data streams, because mirrors only allow delaying a data stream by an even number of ticks, which is sufficient for 2-, 4-, 6-cycle data etc.

The simplicity of the constructions is also helped by the fact that the photon data streams in this system can cross each other without interference (as long as they are kept out of step). Hence in Photonworld no special gadgetry is necessary to care for intersections, which is in stark contrast to many other systems.

If you find other interesting setups for this game, you can email them to me and I might include them in future versions of this game.

More freeware and real puzzles and games at my homepage: http://karl.kiwi.gen.nz.