Among NFL rule change proposals is a fourth-and-15 play replacing an onside kick
Teams that score a pick-six take Super Bowl -- Tuesday Morning Quarterback - ESPN
I'll Believe In Anything; You'll Believe In Anything
NFL owners vote: fourth-and-15 onside kick alternative will improve NFL - Arrowhead Pride
The NFL's onside kick revolution is upon us!
What is the XFL's 4th and 15 rule, and how is it different from the NFL? The onside kick rule explained
NFL owners vote: fourth-and-15 onside kick alternative will improve NFL - Arrowhead Pride
NFL Rule Changes 2019: “4th and 15” onside kick alternative rejected by team owners - Field Gulls