You probably haven't heard of cellular automata. Here is an explanation:
The universe consists of a grid of cells that are either on or off. The state of a cell in the next generation is decided based on the rule, its state, and the state of the surrounding 8 cells, like this:
bbb
bab
bbb
The rule will look something like this: b3/s23. What this means is, if a cell is off then it will only turn on if exactly 3 cells are surrounding it, and if it is on then it will stay on only if it is surrounded by 2 or 3 cells. A rule can have any of these: b12345678/s012345678. Just ignore what happens with b0 because it is very weird.
Here is the best program that plays it:
http://www.xs4all.nl/~jbontes/There are many types of interesting objects but I am most interested in gliders. A glider is a pattern that reappears in a different place after a certain number of generations. The program that I wrote searches for gliders.
A glider can be very small, like this:
#R B35678/S34678
.o..
.ooo
oo.o
ooo.
.o.o
.oo.
Gliders can also be very large and yet still be found easily:
x = 12, y = 46, rule = B357/S1358
o2bo4bo2bo$o10bo$2bobo2bobo$2b3o2b3o$2b2o4b2o$3bo4bo2$3b2o2b2o$
2o8b2o$2bo2b2o2bo$2obob2obob2o$b2o6b2o$4b4o$3b2o2b2o$5b2o$3b6o$3b
o4bo$5b2o$3bob2obo$4b4o2$4b4o$4b4o$3bo4bo$5b2o$4b4o$b2ob4ob2o$bo
bo4bobo$2b2o4b2o2$3bob2obo$3bo4bo$4bo2bo2$4b4o$3bo4bo$2bo2b2o2bo
$2bo6bo$2bobo2bobo$3bo4bo$3bob2obo$b2obo2bob2o$o2b6o2bo$b3ob2ob3o
$b2obo2bob2o$2bob4obo!
To view one of those gliders you must copy it, and then paste it into the program that I put a link to way up yonder in this post. The second one is encoded so it doesn't take up as much space. My program usually finds gliders instantly if they are small. The second glider took a few seconds.