Update

mechanical.md

@@ -65,7 +65,7 @@ Besides others gears/wheels can be used to:
  |    '-;,     ,-;'   { o } |
  |    _|||____{ o }____;-;  |
  |             '-;-.  { o } |
- |_____________ { o } _'-'__|   
+ |_____________ { o } _'-'__|
                  '-'
                   1
 
@@ -76,7 +76,7 @@ Besides others gears/wheels can be used to:
  |   ,;-'  ,-,  '-'{ o }    |
  |  _|||__{ o }_____;-;     |
  |         '-'   .-{ o }    |
- |_____________ { o }-'_____|   
+ |_____________ { o }-'_____|
                  '-'
                   0
 ```
@@ -199,4 +199,4 @@ Whether the use of fluids/gases (water, air, steam, maybe even sand, ...) is sti
 
 Don't forget there exist many other possible components and concepts a mechanical computer can internally use -- many things we leave out above for the questionability of their practical usability can be used to in fact carry out computation, for example dominoes or slinkies. Furthermore many actually useful things exist, e.g. teethed **cylinders/disks** may be used to record plots of data over time or to store and deliver read/only data (e.g. the program instructions) easily, see music boxes and gramophones; **[punch card](punch_card.md) and paper tapes** have widely been used for storing read-only data too. Sometimes deformed cylinders were used as an analog **2D [look up table](lut.md)** for some mathematical [function](function.md) -- imagine e.g. a device that has input *x* (rotating cylinder along its axis) and *y* (shifting it left/right); the cylinder can then at each surface point record function *f(x,y)* by its width which will in turn displace some stick that will mark the function value on a scale. To transfer movement **strings, chains and belts** may also be used. [Random number generation](rng.md) may be implemented e.g. with [Galton board](galton_board.md). If timing is needed, pendulums can be used just like in clock. Some mechanical computers even use pretty complex parts such as mechanical arms, but these are firstly hard to make and secondly prone to breaking, so try to avoid complexity as much as possible. Some old mechanical calculators worked by requiring the user to plug a stick into some hole (e.g. number he wanted to add) and then manually trace some path -- this can work on the same principle as e.g. the marble computer, but without needing the marbles complexity and size are drastically reduced. Another ideas is a "combing" computer which is driven by its user repeatedly sliding some object through the mechanism (as if combing it) which performs the steps (sequential computation) and changes the state (which is either stored inside the computer or in the combing object).
 
-BONUS THOUGHT: We have gotten so much used to using our current electronic digital computers for everything that sometimes we forget that at simulating actual physical reality they may still fail (or just be very overcomplicated) compared to a mechanical simulation which USES the physical reality itself; for example to make a simulation of a tsunami wave it may be more accurate to build an actual small model of a city and flood it with water than to make a computer simulation. That's why aerodynamic tunnels are still a thing. Ancient NASA flight simulators of space ships did use some electronics, but they did not use computer graphics to render the view from the ship, instead they used a screen projecting view from a tiny camera controlled by the simulator, moving inside a tiny environment, which basically achieved photorealistic graphics. Ideas like these may come in handy when designing mechanical computers as simulating reality is often what we want to do with the computer; for example if we want to model a [sine](sin.md) function, we don't have to go through the pain of implementing binary logic and performing iterative calculation of sine approximation, we may simply use a pendulum whose swinging draws the function simply and precisely.
+BONUS THOUGHT: We have gotten so much used to using our current electronic digital computers for everything that sometimes we forget that at simulating actual physical reality they may still fail (or just be very overcomplicated) compared to a mechanical simulation which USES the physical reality itself; for example to make a simulation of a tsunami wave it may be more accurate to build an actual small model of a city and flood it with water than to make a computer simulation. That's why aerodynamic tunnels are still a thing. Ancient NASA flight simulators of space ships did use some electronics, but they did not use computer graphics to render the view from the ship, instead they used a screen projecting view from a tiny camera controlled by the simulator, moving inside a tiny environment, which basically achieved photorealistic graphics. Ideas like these may come in handy when designing mechanical computers as simulating reality is often what we want to do with the computer; for example if we want to model a [sine](sin.md) function, we don't have to go through the pain of implementing binary logic and performing iterative calculation of sine approximation, we may simply use a pendulum whose swinging draws the function simply and precisely.