Analogy: Constructions and Proofs

Constructions are very similar to proofs. It's plausible that the very concept of "proof" had its roots in the idea of geometric construction in ancient Greece. In Euclid's "Elements," the ideas of construction and proof are intertwined.

Here's a chart emphasizing the similarities between constructions and proofs.
 

CONSTRUCTION

PROOF

Input: Starting point ("Givens" in GSP)

Hypothesis

Basic construction rules (the Construct menu in GSP).
Each step of the construction uses something already constructed, and the basic rules.

Basic proof rules: axioms and rules of logic.
Each step of the proof uses something already proved, and the basic rules.

Output: Result of the construction

Conclusion