apple-pascal-1.3-manual

When you press RETURN, program SPIRODEMO (alias WHILEPLOT)begins to draw its design on the screen, using the parameters that youspecified.On completion of the design, the program continues to display the designuntil you press any key on the Apple's keyboard. Just press the SPACE bar,and the original prompt will replace the design on the screen. You are thenready to specify a new CHANGE and DISTANCE for another design (orspecify an ANGLE of zero to quit the program).ICaution: This program is terminated if the first character of an ANGLEor CHANGE response is not a plus sign, a minus sign, or a numeric digit.Program SPIRODEMO contains examples of the following:o Using the TURTLEGRAPHICS unit, including the KEYPRESS functiono Reading the keyboard buffer without echoing on the screenThe HILBERT ProgramHILBERT shows a historically famous example of recursion, using aspace-filling design to create an attractive display on the screen.You can determine the density of the space-filling design by specifying aninteger ORDER from 1 through 7.When you execute HILBERT.CODE, this message appears:Enter ORDER 0 to quit.ORDER:If you wish to quit the program at any time, wait until this message appears,and then type a zero. If you wish to continue, you must type an integer from1 through 7. An ORDER of 1 fills the space most "loosely," taking barely onerepetition of the design to fill the screen. Each higher order fills the screenmore and more densely, by repeating the basic design on a smaller andsmaller scale. Order 7 fills the screen to solid white, and takes quite a longtime doing it. There is no way to stop a display while it is being created,except to press CONTROL-RESET. To get the idea, respond by typing4II-310Appendix 2F: Demonstration Programs