It’s the 4th of July and in addition to mutant hordes roaming suburban backyards looking for an angry fix of grilled flesh, that means explosives. When I was young, we went to Seattle’s Gasworks Park to watch the fireworks and when I asked my parents why I couldn’t light the fuses of the massive ballistics they told me that the pyrotechnics experts had special moves that allowed them to dodge falling debris. I practiced those moves. They also told me that the experts had to know *exactly* when to light every fuse so as to A) create a visually appealing spectacle, and B) avoid being blown into bloody little chunks. My parents also told me about the “bomb fires” that dotted the neighborhoods.
All told, it was a little traumatic.
And so now I hope to share this trauma: how can our pyrotechnician light these seven fuses without finding himself next to any explosion? Specifically, starting at time zero, he must light one new fuse every five subsequent seconds (no waiting one second to offset the explosions!). Each fuse takes the indicated time to burn after which the bomb it infuses instantly goes boom. If our pyrotechnician is lighting a fuse at the same time that a bomb next to it explodes, he’s toast. It takes no time to travel between fuses. How can safely set off these explosions in the shortest amount of time?