Atom or cell
------------
`$|` is a tile rune that produces a [`%reed`](), a tile whose [icon]()
is a [fork]() between two nouns: an [atom]() of `tile` `p` and a cell of
`tile` `q`. `$|` is similar to [`$?`](), but is more strict in that in
only contains one atom tile and one cell tile.
### Produces
[`Tile`](): `[%reed p=tile q=tile]`
### Sample
`p` is a [`tile`]() `q` is a [`tile`]()
### Tall form
$| p
q
### Wide form
$|(p q)
### Irregular form
None
### Examples
~zod/try=> *$|(~ [~ u=@])
~
~zod/try=> :type; *$|(~ [~ u=@])
~
u(@)
++ list |* a=_,* :: null-terminated list
$|(~ [i=a t=(list a)]) ::
In `++list`, `$|` specifies that every element in a noun that can be
cast to a `++list` is either the atom `~` or the cell
`[i=a t=(list a)]`.