Say you want to create a balloon and have it float around the sky.  The
balloon could be designed as in the 24 by 21 grid:


                          SERIES |SERIES |SERIES
                             1   |   2   |   3
                                 |       |
                          1       1       1
                          2631    2631    2631
                          842684218426842184268421
                         +------------------------+
                       1 |.........#######........|
                       2 |.......###########......|
                       3 |......#############.....|
                       4 |......#####...#####.....|
                       5 |.....#####.###..####....|
                       6 |.....#####.###.#####....|
                       7 |.....#####.###..####....|
                       8 |......#####...#####.....|
                       9 |......#############.....|
                   R  10 |......#############.....|
                   O  11 |......#.#########.#.....|
                   W  12 |.......#.#######.#......|
                      13 |.......#..#####..#......|
                      14 |........#..###..#.......|
                      15 |........#..###..#.......|
                      16 |.........#..#..#........|
                      17 |.........#..#..#........|
                      18 |..........#####.........|
                      19 |..........#####.........|
                      20 |..........#####.........|
                      21 |...........###..........|
                         +------------------------+
                                   1    1    2   2
                          1   5    0    5    0   4

                                   COLUMN

  The  next  step is to convert the graphic design into data the computer
can use.  Get a piece of notebook or graph paper and set up a sample grid
that  is  21 spaces down and 24 spaces across.  Across the top write 128,
64,  32,  16,  8,  4,  2,  1,  three  times (as shown) for each of the 24
squares.  Number down the left side of the grid 1-21 for each row.  Write
the  word  DATA  at  the  end  of each row. Now fill in the grid with any
design or use the balloon that we have. It's easiest to outline the shape
first and then go back and fill in the grid.
  Now  if  you  think  of  all  the  squares  you  filled in as "ON" then
substitute  a 1 for each filled square.  For the one's that aren't filled
in, they're "OFF" so put a zero.
  Starting  on  the  first  row,  you need to convert the dots into three
separate  pieces of data the computer can read.  Each set of 8 squares is
equal to one piece of data called a byte in our balloon. Working from the
left,  the first 8 squares are blank, or 0,  so the value for that series
of numbers is 0.
  The  middle series looks like this  (again a 1 indicates a dot,  0 is a
space):

              128    64    32    16    8     4     2     1
            +-----+-----+-----+-----+-----+-----+-----+-----+
            |  0  |  1  |  1  |  1  |  1  |  1  |  1  |  1  |
            +-----+-----+-----+-----+-----+-----+-----+-----+
               ^     ^     ^     ^     ^     ^     ^     ^
               |     |     |     |     |     |     |     |
               0  +  64 +  32 +  16 +  8  +  4  +  2  +  1  =  127


  The  third  series  on  the first row also contains blanks, so it, too,
equals zero. Thus, the data for the first line is:

                             DATA 0, 127, 0

  The series that make up row two are calculated like this:

            +-----+-----+-----+-----+-----+-----+-----+-----+
  Series 1: |  0  |  0  |  0  |  0  |  0  |  0  |  0  |  1  |
            +-----+-----+-----+-----+-----+-----+-----+-----+
                                                         1  =  1

            +-----+-----+-----+-----+-----+-----+-----+-----+
  Series 2: |  1  |  1  |  1  |  1  |  1  |  1  |  1  |  1  |
            +-----+-----+-----+-----+-----+-----+-----+-----+
               ^     ^     ^     ^     ^     ^     ^     ^
               |     |     |     |     |     |     |     |
              128 +  64 +  32 +  16 +  8  +  4  +  2  +  1  =  255

            +-----+-----+-----+-----+-----+-----+-----+-----+
  Series 3: |  1  |  1  |  0  |  0  |  0  |  0  |  0  |  0  |
            +-----+-----+-----+-----+-----+-----+-----+-----+
               ^     ^
               |     |
              128 +  64                                     =  192

  For row 2, the data would be:

                            DATA 1, 255, 192

  In the same way, the three series that make up each remaining row would
be converted into their decimal value.  Take the time to do the remainder
of the conversion in this example.
  Now  that you have the data for your object,  how can it be put to use?
Type in the following program and see what happens.