mefoghorn said:
What are the stamps for? Just decorative?
Also, I've always wondered: Why do we cut grooves into sidewalks and section out concrete? It doesn't go all the way through, so it's not like each section can move separately. Is it meant to be a stress concentration in the hopes that any big cracks will occur within the groove?
Correct, the stamps are just decorative.
And the grooves that they cut are called control joints. They are designed to control where the concrete cracks, because concrete will always crack.