Notice that the angle is steeper and the two lines are closer together. This is because each individual column now overlaps the next one. Notice also that it prints more slowly, although with this amount of printing the difference in speed may be hard to detect.
Now try double density, normal speed (ESC Y):
30LPRINT CHR$(27);CHR$(89);CHR$(11);CHR$(0);CHR$(1); CHR$(2);CHR$(4);CHR$(9);CHR$(18);CHR$(36);CHR$(72); CHR$(144);CHR$(32);CHR$(64);CHR$(128)
Aside from printing speed, there should be no difference, because the pattern does not include adjacent dots; if it had, some dots would have been skipped.
Finally, try quadruple density (ESC Z):
40LPRINT CHR$(27);CHR$(90);CHR$(11);CHR$(0);CHR$(1); CHR$(2);CHR$(4);CHR$(18);CHR$(36);CHR$(72); CHR$(144); CHR$(32);CHR$(64);CHR$(128)
Compare the results:
The angle is even steeper, and the two lines have merged into one thick line because of even greater overlap.