It isn't every day that you see something like this.

This is the reason you check all markers before you work on them.

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This was the result of working on our law-rocket launcher without checking to see if there was a football in it. The football went through the office, through my front window, across the parking lot and onto our neighbor's lawn. Luckily, nobody was hurt. A couple of inches to the left and the ball would have bounced harmlessly off of the wall (or stuck in it). Just my luck to have it take out the front window of my house.