+
    `Push a bunch of facts.`
    0 b
    1 a 1 b 1 c
    1 d 1 e 1 f
    1 e 1 d 1 c
    1 a
.

`Did we find what we're looking for?`
? 0 $a 1 $a
    - 0
    + 2 $a
.

`Put unrelated items to the side.`
? 0 $a 1 $b
    - 1
    + 3 $b
.

`We couldn't find what we were looking for.`
? 0 $a
    - 0
    + 4 $a
.