YOU SAID:
This mailbox is mine, and this triaginal sign
INTO JAPANESE
このメールボックスは私のもの、この三角標識は私のものです
BACK INTO ENGLISH
This mailbox is mine, this triangle is mine
INTO JAPANESE
このメールボックスは私のものです、この三角形は私のものです
BACK INTO ENGLISH
This mailbox is mine, this triangle is mine
That didn't even make that much sense in English.