Disk Pitcher ID please

HI,
I just bought a nice disk pitcher and cannot figure out who or what it is. It has no marking on the base and none inside. The base is flat without a raised edge like the Fiesta ones I've seen. Any help would be appreciated.

It's certainly very similar to Fiestaware ....

Is it possible that it is very old Fiesta without any markings?

Interesting site http://www.happyheidi.com/antiques/history_of_riviera.html
explains about two ranges -Harlequin and Riviera -similar to Fiesta, unmarked but also made by Homer Laughlin. I can't see anything that exactly matches your jug, but worth a look.