In any case, Whirlwind suggested that since our itinerary included seeing both the Grand Canyon and Hoover Dam (sites where a couple of events in the books take place), we make Camp Half Blood t-shirts. Camp Half Blood is where Percy Jackson and all the other demi-gods go each summer to escape the monsters from mythology. They learn to fight, use their talents and, more often than not, go on quests. Their t-shirts are orange with a Pegasus and the name Camp Half Blood on them.
I found the graphic online and converted it into an SVG file so I could cut it using my Silhouette Cameo. I used the freezer paper technique to create the stencil. I used Safety Orange shirts--which had the added benefit of making my family really easy to spot anyplace we were at. Having had a child wander off before, I also know it's really easy to say to employees, "My child is wearing a shirt exactly like mine," and then everyone knows what to look for.
Then I used a combination of black Sharpie and black paint to fill in the blank parts of the stencil. You must make sure you have something between layers of shirt to protect the backside from getting colored/painted on.
Finished product (against record low levels of the Hoover Dam).
