As the next installment in our "A confession of stupidity" series [1], I never realized that before. :) Turns out that superimposing chars on top of each other to make other chars is an addictive game, though. Here are a few I came up with:
|S => $
:, => ;
++++ or //= => #
o/o => %
ao or aO => @
\S => &
-x or -X => *
|_ => L
/-\ => A
|3 => B
][ => I
|-| => H
C- => G
|= => F
|^^| => M or m
|< => K
|? or |> => P
|o => b
|) => D
-/_ => z
O, => Q
-| => +
|\| => N
bP => B
Unfortunately, few if any of these could be useful for Arc.