And they tried to find the meaning:
12 square 3: the shape in the tattoo is considered "square" or it is also a calculation in maths (^2).
* 1+ 2 =3, 2.21 & 2.23 in which 21.2 & 23.2 are JJY & YM birthdays, respectively
* 1 (2 square) 3 = 1(2^2)3 = 143, in which there is a song named 143 (I Love You) by Henry. In addition, when you search in Urban Dictionary, there is also a mention of 143 means "I Love You" (http://www.urbandictionary.com/define.php?term=143)