🚀 go-pugleaf

s2874066@techst02.technion.ac.il (Eyal Peleg) writes:
>  Draw a vertical line that starts from home [0 0] and ends at [0 90],
>  This line should not be a continuous one but should be 4 pixels on and 1 off
>  something like "---- ---- ---- ---- ---- ...."

Boy, when I read this message the first time I thought "that's trivial, what's
the deal?"  But when I actually tried it I learned two things, one was the
fencepost problem about pixels, and the other is that it's even harder in
Berkeley Logo, because it tries to set the aspect ratio according to what the
graphics hardware says is right, and for my CGA laptop that comes out some
non-integer ratio.

(Berkeley Logo tries to arrange things so that FD 100 fits within the
splitscreen graphics area.  For CGA that turns out to mean that one
vertical turtle step is only (about) half a screen pixel.  If I make it
exactly half a screen pixel, I can get the desired dotted line with
PD FD 2 PU FD 3!!  If I use the setting that Berkeley Logo comes up with
on its own, there's no way I can get uniform dotted lines.  You can't win.)