1.2) Smart Contract Interact
    - Sending transactions 
    - Calling functions
    - Transferring value between contracts

1.1) Block Limit limits interaction
    - The block limit in Ethereum refers to the maximum amount of gas that can be consumed in a single block. 
    - This gas limit is set to ensure the network's stability and prevent abuse by excessively complex or resource-consuming transactions.

1.3) Expensive OpCodes
    - Expensive opcodes in Ethereum refer to instructions that consume a significant amount of gas when executed. 
    - These operations often involve complex computations, large storage access, or cryptographic operations, resulting in higher gas costs.
    
    1.3.1) SHA-256 Hashing: 
        - The SHA-256 opcode is computationally intensive and requires significant gas due to its cryptographic nature.

    1.3.2) ECDSA Signature Verification: 
        - Verifying digital signatures using the ECDSA opcode involves complex elliptic curve cryptography, making it gas-intensive.

1.4) Cheap OpCodes
    - Cheap opcodes, on the other hand, are instructions that consume relatively less gas when executed. 
    - These operations are less resource-intensive and include simple arithmetic operations, basic storage access, or logical operations, resulting in lower gas costs.

    1.4.1) Addition (ADD): 
        - The ADD opcode performs simple addition of two numbers and consumes a moderate amount of gas.

    1.4.2) Storage Access (SLOAD): 
        - Reading a value from storage using the SLOAD opcode is comparatively inexpensive than complex operations.

1.5) Free OpCodes
    - Free opcodes are specific instructions that do not consume any gas when executed. 
    - These operations typically include certain no-op (no-operation) instructions or functionalities that are subsidized by the protocol, allowing them to execute without gas costs.

    1.5.1) No-Operation (NOP): 
        - NOP opcode performs no operation and doesn't consume gas. It's used for various purposes like padding or placeholders.

    1.5.2) Self-Destruct (SELFDESTRUCT): 
        - The SELFDESTRUCT opcode allows a contract to destroy itself and send remaining Ether to a specified address, with no gas cost for the destruction.

Ether Processing Overhead Elimination: Non-payable functions in Ethereum smart contracts bypass Ether processing, reducing gas costs associated with Ether transfers or value manipulations during function calls.

Gas Savings for Etherless Operations: Transactions calling non-payable functions have lower gas costs since no Ether is sent or processed. This optimizes gas usage for operations not involving Ether transactions.

    Fee Market Change: 
        - EIP 1559 alters how transaction fees are calculated and managed within Ethereum, introducing a new transaction pricing mechanism.

    Base Fee & Inclusion Priority: 
        - The proposal introduces a base fee, which dynamically adjusts based on network demand. Users specify an optional inclusion priority (tip) for faster transaction processing.

    Predictable Fees: 
        - Users have more predictability regarding transaction fees due to the base fee's predictable adjustment based on network congestion.

How To Optimize gas usage?:
    a) Minimizing Storage Use: 
        - Reducing the number of storage slots utilized by a contract can lower gas costs. 
        - Using fewer storage slots means fewer write operations, leading to reduced gas consumption.

    b) Compact Data Structures: 
        - Optimizing data organization within storage slots can save gas. 
        - Storing related data together or using packed data structures reduces the number of slots needed and, consequently, the gas required for storage operations.

    c) Layout Efficiency: 
        - Careful planning of data layout within storage slots can optimize gas usage. 
        - Grouping related data together and avoiding fragmentation can minimize gas costs for read and write operations.

    d) Reuse and Cleaning: 
        - Reusing storage slots by updating existing data instead of creating new slots whenever possible can optimize gas usage. 
        - Cleaning or reusing slots instead of leaving unused slots can prevent unnecessary gas consumption.
            aa) Setting to Zero:
                - Clearing Storage: Setting variables or storage slots to zero is a technique used to clear or reset data stored in a contract's state variables or storage slots.
            bb) Refunds
                bb1) Self-Destruction Mechanism: 
                        - When a contract self-destructs (also known as self-destructing or "suicide"), Ethereum refunds excess gas to the sender.

                bb2) Refundable Gas: 
                        - Refunds occur for gas that remains unused after contract execution or self-destruction. 
                        - The refunded gas is a portion of the gas paid upfront for the transaction.

Considerations for Optimization:
    e) Storage Cost Calculation: 
        - The gas cost for storage operations is directly related to the number of slots used and the amount of data stored. 
        - Understanding the gas cost calculations is essential for efficient slot utilization.

    f) Contract Architecture: 
        - Designing contracts with efficient data structures and managing state variables effectively can impact gas efficiency.

    g) Dynamic versus Static Data: 
        - Dynamic data structures, such as arrays and mappings, often require more gas due to potential storage expansion. 
        - Employing fixed-size or more predictable data structures can optimize gas usage.

    a) Memory Expansion: 
        - Gas costs increase when memory expands dynamically, such as when using arrays or dynamic data structures. 
        - Reducing unnecessary memory expansion through optimized data structures and fixed-size arrays can lower gas consumption.

    b) Memory Cleaning: 
        - Cleaning or resetting memory locations after use prevents leftover data, optimizing gas usage. 
        - Efficient memory management involves deallocating or clearing memory slots to reduce subsequent gas costs.

Considerations for Gas Optimization:
    c) Data Packed Structures: 
        - Organizing data in a compact manner within memory slots minimizes memory usage and reduces gas costs associated with memory operations.

    d) Data Access Patterns: 
        - Optimizing how data is accessed in memory—by minimizing reads or writes—can improve gas efficiency during contract execution.