Pro-SiMPLE
Int z[]={0,4,2,6,1,5,3,7,8,12,10,14,9,13,11,15}
Int a, b, xsize, ysize, zbits, rgb
Open a ("read C:\\PICTURE.BMP")
Open b ("write C:\\HIDDEN.BMP")
skip (18) @
Read binary a (a, 0)
Write binary b (a, 0)
Read binary a (b, 0)
Write binary b (b, 0)
xsize=a+256*b
skip (2) @
Read binary a (a, 0)
Write binary b (a, 0)
Read binary a (b, 0)
Write binary b (b, 0)
ysize=a+256*b
skip (4) @
Read binary a (zbits, 0)
Write binary b (zbits, 0)
skip (25) @
If (zbits!=4)
   Display "The picture is not a 16-color bitmap image"
   Close a; Close b
   System ("del C:\\HIDDEN.BMP")
   Pause; Quit
Endif
skip (64) @
Do yy=ysize-1,0
   Do xx=0,xsize-1,2
      Read binary a (rgb, 0)
      rgb=Cycle(rgb-Random(256), 256)
      Write binary b (rgb, 0)
   Loop
   skip ((16384-(xsize+1)/2)%4) @
Loop
Close a
Close b
Quit

Task skip (Int n)
Int data
Do k=1,n,1
   Read binary a (data, 0)
   Write binary b (data, 0)
Loop