If you rotate straight lines by HALF_PI, you will see that they don't line
up straight... everything is slightly off-kilter.

This is because rotate in PGraphics2 takes a float. If you use a double
instead, then everything lines up correctly when rotated. This requires
changing some PConstants to doubles, and PGraphics too.

This bug shows up in 95 on windowsxp. I don't see it on the mac, probably
because the resolution on my powerbook sucks.

it's actually ok on the mac, it's just the sun vm on the pc (and maybe linux?), meaning that
it's a sun bug.

switching to doubles for internal calculations would be way slower and a big mess,
unfortunately. floats have more than enough resolution to properly handle this (esp. since
the mac is ok with it).

could you post the sketch as a zip file? (tools -> archive sketch, then attach it to the bug
report here).

edit]
example of rotate code with skewed lines

thank ye.