GEARS
          
          AMIGOS version of the popular toy that uses geared plastic pieces
          to draw spiral graphs.
          
          The original program was taken from a program featured in BYTE
          magazine several years ago. Its purpose was to  plot hypocycloid
          and epicycloid graph points.  The original program simply gave a
          list of the points. A few years ago I reworked the program to
          plot the graphs on an Intecolor 6120 terminal. This produces
          great results because of the terminals 19" screen and 1024 x 768
          resolution, but alas Intecolor is gone and the commands for the
          graphics terminal are unique to Intecolor.
          
          So, Version 3 - the AMIGOS version of the program - GEARS.

          You may well recognize the toy this looks like.  The idea is to
          have two circles, one stationary and the other rolling.  In a
          epicycloid the rolling circle moves around the outside of the
          fixed circle and in a hypocycloid it moves around the inside.
          A fixed point on the rolling circle plots the graph.  In the
          electronic version there is no problem having the rolling circle
          be either larger or smaller than the fixed. (Something you can't
          do with the plastic version. On the other hand the newest
          versions of the toy come with non-circular tracks so you can make
          some darn fancy graphs.)
          
          To run GEARS be sure you are set up for AMIGOS and have your GDV
          loaded. 
                        Enter RUN GEARS
          
          If gears has been run before a file called GEARS.DAT will be
          found and a list of the last parameters used will be displayed.
          You are the asked the following questions.
          
                        Enter the radius of the fixed circle
                        Enter the radius of the rolling circle
                        Enter the type E)picycloid or H)ypocycloid
                        Enter the amount to increment the step
                        Enter the number of steps
                        Enter the color
          
          If you wish to leave a value the same as last time just enter
          'RETURN' else enter a new value.
          
          Try a variety of values in each field.
          Values for the circles look 'neat & clean' if they are multiples
          of each other but odd values can make interesting results.
          The increment value if low (ie .1) follows the plot in a very
          steady an 'clean' set of lines. Try lots of values here, the
          resulting changes can be very large for a very small change in
          value.
          
          The program has a window of 1024 x 1024 and is placed in the
          center if the world quadrant.  You may therefore use values that
          exceed the size of the window (the result looks like a zoomed in
          view of the graph).  Remember the circle values are the radius so
          a value of 383 is as large as the fixed circle can be before the
          plot moves off the screen.



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