Seeing a red (or white, or blue) flag
I was planning a 4th of July party at my house and needed just the right thing to fill an area along a gravel pathway. Dave and I wanted our guests to walk our paths and discover the all the areas people could go. Earlier that week I noticed my neighbor was doing some landscaping, and in the yard were those little flags to show utility lines.
That was it!!
Found them online, inexpensive and come in lots of wonderful colors, the guests loved them and they became a great part of the overall experience.