🚀 go-pugleaf

I did an equal thing when I was in high school (Crete, Nebraska,
but that is another story). 

On Apple ][ the disk I/O in Basic was done via printing
utilities, chr$(13)chr$(4) was the code to start a DOS command. I
am skipping a lot of details, but one of the commands was new,
which clears the Basic workspace.

Anyway, we were supposed to program something simple in math
class. My program calculated the sides and angles of a triangle.
But besides showing the program we were supposed to give the code
to teacher, too. So I had put several lines of comments in the
beginning of program and then I went to the monitor (like
debugger) mode and changed some blanks in those comments to
carraige returns, backspaces and ctrl-D:s. 

So I turned in the source code and the teacher went happily home
with it. Next day he complained to the class that my program
seems to calculate the triangles all right, but he can't
undestand how it does it, since all he can get with the list
command is a blank screen with my copyright message. I had used
backspaces and blanks to cover the line numbers and placed a CR,
ctrl-D, NEW, CR on the last line, which cleared the buffer. 

Of course this is easy to crack by printing the code on paper,
slowing printing to screen or with a debugger. But at those days
it was a lot of fun. 

Little things like these work still. You can place a ctrl-Z to
the start of MS-DOS file, this stops the type-command. Or having
a line containing only word DISCONNECT in it, does interesting
things with some communications programs. 
--
Timo Kiravuo
Helsinki University of Technology, Computer Center
Tel: work 451 4328, home 676 076, Fax 466 251;  Intl. add +358 0
kir...@hut.fi  sorvi::kiravuo  kiravuo...@uunet.uu.net