Glider

German aeronautical engineer Otto Lilicnthal invents his first glider. 

Conditions are frequently suitable for the formation of lee waves over the mountainous regions of the US, an effect that is routinely exploited by glider pilots to obtain exceptionally high altitudes. The combination of lee waves with strong winds that are sufficient to produce damage to structures is fortunately rare, but do occur in hazardous mountainous regions. 

One of the ino.st intriguing patterns in Life is an oscillatory propagating pattern known as the glider. Shown on the left-hand-side of figure 1.5, it consists of 5 live cells and reproduces itself in a diagonally displaced position once every four iterations. 

Park s glider gun, shown in figure 3.36, starts from the initial configuration S(t = 0) = 00111111111101100 and generates either a left- or right- moving glider once every 238 iterations. 

Fig. 3.36 Space-time pattern of fc = 2, r = 3 tot llistic rule T88 i.e. Park s Glider Gun.

Gliders In Conway s own words [berk82], When we first tracked the R-pentamino. .. some guy suddenly said "Come over here, there s a piece that s walking . We came over and found figure... 3.72. 

This remarkable five five-cell pattern is called a glider because after two iteration steps it produces a pattern that is both diagonally displaced by one site and reflected in a diagonal line - i.e., patterns separated by two steps are related by a glide reflection. In this way, the original pattern is reproduced in a diagonally displaced position every four iterations. 

Fig. 3.71 The R -pentomino s period-two configuration (open circles) reached at time t=1103 six gliders are also produced but are beyond range. The original R-pentamino pattern is shown in solid black.

AND, OR, and NOT gates) of information - can be implemented by the evolution of appropriate Life patterns. Indeed, it will be shown that the circuitry of any computer can actually be constructed out of nothing but gliders, glider-guns, blocks and eatersl... 

Fig. 3.79 A thirteen glider collision at 1 = 0 produces a period p = 30 glider-gun at t = 75, generating a glider once each period.

Fig. 3.81 ScheiTicitic for a Thin Glider Guu E — eater (see figure 3.76), G = glider-gun (see figure 3.79) and K = kickback reaction.

It was mentioned above that in order for the AND gate shown in figure 3.82-b to operate properly, the gliders in input A must be delayed by a time equal to the distance between the two annihilation reactions. The same is true of the operation of the OR gate, shown in figure 3.82-c. 

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