The symbol on Yoshi’s mailbox in Super Mario World is the Japanese postal mark, 〒, that has been used for over 70 years to indicate mailboxes, post offices and other post-related things in Japan.
In Super Mario Bros. 2, pressing Up and Down simultaneously while on a vine will make your character shoot up extremely quickly. Sadly, this is impossible to perform with a regular NES controller unless you break or modify the D-pad.
