Messed up angles

[reuschp]

Hi guys,

I observed another strange effect, when moving the turtle to close to the edge of the drawing area.
This code example stays away from the borders and looks like I would expect:

If I use the same code - but now extend the line length to hit the edge, funny things occur:

As you can see, not only the starting angles of the lines are messed up. They should have almost the same degree between them - which they do not have. Also the 90 degree turn at the end of the first line is far away from being 90 degrees consistently.

This makes it completely unpredictable, how a drawing will look, when you come close to the border even once during the drawing process.

Any suggestions?

Regards
Pascal