block auto
  abbr sharp ♯
  abbr flat ♭
  abbr square □
  abbr rquare ▢
  abbr diam ◇
  abbr iinf ∞
  abbr niinf -∞
  abbr sim ∼
  abbr approx ≃
  abbr cong ≅
  abbr fcomp ∘