Visiting a modern Indian restaurant, I spy these on the window sill. Sometimes they are less practical and are made in attractive china so having a double use as ornaments. They are, in fact, special containers for food storage and easy delivery. Wives in Asian and Middle Eastern countries place each dish they have cooked in each tin dish. Every one of these fits into place forming layers in an airtight and secure portable container.
This is taken to work by the worker or they are collected and delivered to the workplace each day. Amazingly, thousands of these are delivered and there are few mistakes or omissions.