Unki jaan lijiye - Mutual Misty: Offer & Invitation to Treat

Main ek contract law ke concept ke liye confuse rehta hun - offer versus invitation to treat. Dono kaam similar lagte hain, par yeh samajhne ki zarurat hai ki dono hi nahi saman hain. Kuch cases mein offer consider kiya gaya, kuch mein invitation to treat. Jaise ki, Upton on the Four fours case (1937) mein, tea leaves ki sale ke liye ek shop mein display kiya gaya tha, jisme wahi daam likha tha. Ab kya yeh offer tha? Ya invitation to treat? Lagta hai dono hi hain, par kya zarurat hai kuch specific features identify karni hain? Yeh toh confusion banata hai. Koi bhai mere sath share karega kaisa difference hai, please help!