The Funnel & Sphere 3-D program was written by Sol Steinberg and was
published in Stereo World magazine's Nov/Dec 1991 issue.

1) While in DOS, type GRAPHICS and <Enter>.  (Only req'd if you desire
   to print the 3-D image.)
2) Start your BASIC program, load and run 3-D.BAS.
3) Print the image by using the print screen key, or simply view the
   image on your monitor.
4) Press any key to exit the program.

The image produced on the screen is called a Single Image Random Dot
Stereogram.  Another example was published in the November 1991 issue of
Omni magazine.  The technique to viewing stereograms is to aim your eyes
at a point far off in the distance and at the same time focus your
eyes on the image in front of you.  Note that aiming and focusing your
eyes are independent operations.  This will be difficult for some
people, but once you get it, the 3-D image will be plainly evident.
Remember--aim far and focus close.  Happy viewing!