Polkadot

Polkadot's architecture allows Layer 1s connected to it to interact seamlessly with each other and the relay chain.

When transferring tokens or data between two Layer 1s, the source Layer 1 initiates a transfer that is expressed in the XCM (Cross-Consensus Message) format. The relay chain then relays this transfer, routing the message to the destination Layer 1. Upon receipt, the destination Layer 1 processes the XCM message, updating its state with the new tokens or data.

For transfers between Layer 1 and the relay chain, the process is similar. If the origin is a parachain, it sends an XCM message to the relay chain, which then updates its state based on the XCM instructions. Conversely, if the relay chain is the origin, it sends an XCM message to the designated parachain, which then processes the message to update its own state.