Best way to represent "...and this computation comes from somewhere else" in a block diagram?

I have a block diagram with some inputs and outputs (can't share it due to proprietary details).
I need to make a distinction between two types of inputs:
- "uncommitted" inputs that the user is expected to control through some means
- "committed" inputs that come from somewhere else in my system, that I want to refer to but not bring further details. (Kind of like the area west of the Hudson River in the famous New Yorker cover: https://en.wikipedia.org/wiki/View_of_the_World_fr...)
I have a good symbol for uncommitted inputs, they're just a lollipop with the circle meant to denote an input.
Any suggestions for the committed inputs? I was thinking of a square/rectangle to represent a block, but with one half (opposite the block's output) dashed to represent incomplete behavior.

Maybe a pentagon formed by uniting a square with a triangle on its right edge. In other words, the same symbol that is used on schematics when a signal comes from another page.

Neirober-
Right, same as flowchart "connector" symbol. Maybe something indicating type of input inside the symbol (clock, pulse, etc).
-Jeff