Shapes are congruent if (and only if) they are enclosed in the same space vs. not so.
All shapes enclosed in the same space are congruent vs. not so.
Congruent shapes are enclosed in the same space vs. not so.
Congruent objects are enclosed in the same space vs. not so.
Incongruent objects are separated vs. not so.
Non-congruent objects are separated vs. not so.
Non-congruent objects in separate regions vs. not so.
If two objects are enclosed in the same region, they are congruent vs. not so.
Leo Crabbe