I know they're not fiesta (got on FB just for fiesta and these were in there- got some vintage harlequin and riviera pieces!) these are Edwin Knowles and I've done some research
1940s Vintage Harlequin Dishes Made by Homer Laughlin Teacups and Saucers Sold Separately. - Etsy
Sold at Auction: Collection of Anodised Aluminium Goblets "Fiestaware" - including 6 wine goblets and 4 champagne, harlequin colours with chromed to bases. Wines 13cm high, champagne 15.2cm
Vintage MCM Homer Laughlin Harlequin Fiesta Ware Bright Yellow - Etsy
Fiesta Harlequin Fiestaware RARE Gray Homer Laughlin Covered - Etsy
Vintage Fiesta ware, Harlequin, Riviera and Caliente dishes for Sale in Seattle, WA - OfferUp
Vintage Harlequin dinnerware by Homer Laughlin for Woolworths for Sale
VINTAGE harlequin by Homer Laughlin Sugar Bowls - Etsy