I've not seen heads that cover other than a circular, or semi-circular,
area, with the exception of drip watering systems.

For my rectangular front lawn (all heads from one line on the long edge
of the rectangle; a line on each long edge would probably be better, but
more work), I have quarter circle spray heads at each end, and half
circle spray heads along the edge, with enough that each area is covered
by two heads. I also have some long rectangular flower beds and I put
in drip irrigation there, which works well with flower beds, but I don't
know how it would work with a lawn.

I visited Rainbird's site (I have their system) and was disappointed to
see that they apparently no longer offer a self-design service; you have
to send them a map and rely on their design. Perhaps too many people
could not handle the volume and pressure calculations and were mis
designing their own system. I also noted that the local store they list
as carrying their product in fact does not carry their product (I
visited the store), but a local irrigation supply house accommodated me,
and I always expect that products sold through suppliers are of a
superior grade to those sold to the public. Also, some of the drip
supply pieces that I got some years ago are apparently no longer made.

I'm happy with my rainbird system, but their web site and distribution
don't seem to be as good as they were a few years ago; I'd be inclined
to check out the other brands now.

fb wrote:
We need to include several rectangular areas in our sprinkler system.
These areas are 5 x 15, 4 x 14, and 4 to 5 x 17. The Toro catalog
illustrates side, center, and end strip patterns as all rectangular.
The Rainbird catalog shows the center strip shaped like a bow tie
(spraying wider from a narrow center) and the end strip as half a bow
tie (spraying from narrow to wide). If you've had actual experience
sprinkling rectangles, your advice would be appreciated.