I'm aware that "●▲■" is a famous drawing from a Zen Buddhist priest by the name of Gibon Sengai. This drawing can be interpreted in different ways but the most common is that the circle represents reality/mind, the triangle represents a human, and the circle the earth. Other definitions are related to design(1,2); as placeholders(each of the singer's names is represented by a shape). But I don't think this applies to this context. Also, the meaning of these shapes discussed here doesn't apply in this case either since there are other symbols used too (★,◆,▼).
Some examples of titles of threads from 2ch/5ch:
- ■■■ 米国のエイズ感染者数は2000万人以上 ■
- ●▲■語彙は力なり その22◆▲●
At first I thought the only combination being used was ●▲■, but as you can see in the examples there are different combinations like ●■▲ and ■▲●, so I guess the order is of the shapes matter. In cases like ex 5 the ★ and ●▲■ appear to be used as brackets and the order of ●▲■ is not reversed. In other cases it's reversed like in 8. In ex 2 and 3 they don't appear to be used as brackets.
Is there any special meaning of using this characters in different combinations? (mostly in thread titles in 2ch?