Soviet-era polka dots

milk-canI have been seriously crushing over these Soviet-era polka-dot kitchenware designs of late. tin-cannisters enamel-pottea-cup vintage clock ceramic-pitchersugar-and-cream coffee-cups tea-potsquare-cannisters porcelain-bowls enamel-cupsThe red I understand. But can anyone tell me what was behind the polka dots?

{Image links - all on Etsy: 1. milk can 2. tin canisters 3. enamel pot 4. tea cup 5. vintage clock 6. ceramic pitcher 7. sugar bowl & creamer 8. coffee cups 9. tea pot 10. square canisters 11. porcelain bowls 12. enamel cups}