(seek origin target (? step-by 1))
  origin: a num
  target: a num
  step-by: a num (optional)
  returns a num
F

Moves closer to a target value.

When (== origin target), returns target.

When (< origin target), returns (min target (+ origin step-by)).

When (> origin target), returns (max target (- origin step-by)).

smoothstep
antiseek